(Latest update: February 17, 2011. This article will no longer be updated. Please see CNET's guide to 3D TV for an updated alternative.)
It's been almost a year since the first of the "new" 3D TVs, enabling their owners to watch 3D Blu-ray movies and 3D television programming as well as play 3D games. The technology behind these televisions is still relatively new, however, and still inspires plenty of questions.
In this newly updated FAQ I'll attempt to answer those questions as well as possible, incorporating my first-hand knowledge in reviewing numerous 2010 3D TVs, conversations I've had with industry experts, and reactions from readers.
This article is targeted toward people looking for an introduction to modern 3D TV technology. If you're an advanced reader just looking for the latest news your best bet is going straight to CNET's 3D TV resource guide.
Table of Contents
3D TV basics
1. What is 3D TV?
2. How does 3D TV work?
3. How is the new 3D TV technology different from older 3D?
4. How is 3D TV different from 3D in the theater?
5. What's the difference between active and passive 3D?
6. Can everyone see 3D?
7. I've heard 3D causes headaches. Is that true?
8. What do I need to watch 3D TV at home?
3D content: movies, TV shows and games
9. Does the movie, TV show or video game need to be in 3D?
10. How many 3D Blu-ray discs are available now?
11. What about older 3D DVDs and Blu-ray discs?
12. What TV shows and networks are in 3D now?
13. Are there any 3D video games?
14. Do any Internet streaming services offer 3D?
3D hardware: TVs
15. Do I need a new TV?
16. How much more do 3D TVs cost?
17. Can the 3D feature on a 3D TV be turned off?
18. Can a 3D TV convert 2D movies, shows and games to 3D?
19. Do 3D TVs use more power?
20. Will 3D TVs work with all 3D formats?
3D hardware: glasses
21. Do 3D TVs come with glasses? How many pair?
22. Can I use any 3D glasses with any 3D TV?
23. Does everyone watching a 3D TV need to wear the glasses?
24. Can I wear 3D glasses over regular glasses?
25. Can I lie down while wearing the glasses? Can I surf on my laptop?
26. I hate 3D glasses. When will we get glasses-free 3D TV?
Other 3D TV hardware
27. Do I need a new Blu-ray player, cable box, game console, or AV receiver?
28. Can I use my existing HDMI cables?
29. Are there any 3D cameras and camcorders?
CNET's reviews and opinions on 3D TV
30. Where can I find CNET's reviews of 3D TVs and other 3D gear?
31. Which is better: Active or passive 3D TV?
32. Do you prefer plasma or LCD 3D TVs?
33. What is crosstalk?
34. What are some other video quality issues with 3D TV?
35. Seriously, is 3D TV any good or just the latest gimmick to get me to buy new crap?
36. I'm thinking of buying a new TV. Is 3D a feature I need?
3D TV basics
3D TV is a generic term for a display technology that lets home viewers experience TV programs, movies, games, and other video content in a stereoscopic effect. It adds the illusion of a third dimension, depth, to current TV and HDTV display technology, which is typically limited to only height and width ("2D").
A 3D TV works much like 3D at the theater. A screen showing 3D content displays two separate images of the same scene simultaneously, one intended for the viewer's right eye and one for the left eye. The two full-size images occupy the entire screen and appear intermixed with one another--objects in one image are often repeated or skewed slightly to the left (or right) of corresponding objects in the other--when viewed without the aid of special 3D glasses. When viewers don the glasses, they perceive these two images as a single 3D image, a process known as "fusing."
The system relies on a phenomenon of visual perception called stereopsis. The eyes of an adult human lie about 2.5 inches apart, which lets each eye see objects from slightly different angles. The two images on a 3D TV screen present objects from two slightly different angles as well, and when those images combine in the viewer's mind with the aid of the glasses, the illusion of depth is created.
Most people are familiar with the old anaglyph method, where a pair of glasses with lenses tinted red and cyan (or other colors) is used to combine two false-color images. The result seen by the viewer is discolored and usually lower-resolution than the new method.
The principal improvements afforded by new 3D TV technologies are full color and high resolution--full 1080p HD resolution for both eyes in see #5)., for example, and half that resolution in broadcast 3D used by DirecTV and other providers. Note that current passive 3D TV technology affects adversely resolution (
(Note: For the remainder of this article, any mention of "3D" refers to the new full-color version, not the old anaglyph variety.)
Many viewers have experienced newer 3D presentations, such as IMAX 3D, in movie theaters. Though the technologies can differ somewhat--most U.S. theaters use passive glasses, for example (see #5)--the main practical differences between 3D TV in the home and theatrical 3D are the size of the screen and the distance you sit from it.
In the home the image is generally much smaller, occupying a lower percentage of viewers' fields of vision, so it's generally less immersive. With 2D you could create a more immersive home theater by sitting closer to the screen, but with 3D that can become a problem. Panasonic recommends a seating distance of no closer than 3x the screen height away--about 6.2 feet from a 50-inch screen--and cautions that sitting closer could increase the risk of eye fatigue and headaches. One expert we talked to, Martin Banks of UC Berkeley, see #7).that sitting too close to a 3D screen can heighten the risk of such adverse effects (
Smaller screens may also present other issues unique to 3D, such as a relatively narrow viewing distance range. We've also seen that the edge of the image, which is much more noticeable with smaller screens, can disrupt 3D viewing much more disconcertingly than 2D.
One advantage of 3D TV at home as opposed to the theater is user control. Some 3D compatible TVs provide control over the 3D experience in addition to standard picture settings. Samsung's models, for example, allow you to adjust the "G axis," or the amount of 3D effect, to taste, comfort or to compensate for variations in eye spacing.
Most 3D TVs use active liquid crystal shutter glasses, which work by very quickly blocking each eye in sequence (typically 120 times per second) to separate the different right and left images required for 3D. The glasses, in addition to the liquid-crystal lenses, contain electronics and batteries (good for 80 or more hours and often rechargeable) that sync to the TV via an infrared or (in many 2011 models) RF signal. They currently cost $60-$120 per pair when sold separately.
In 2011 Vizio, LG and Toshiba will introduce 3D TVs that use passive polarized 3D glasses that are much less expensive. They are actually compatible with the passive 3D used in theaters, and will work with Real D's circular polarized glasses, for example, which are available for as little as $5 each online. The 2011 models use a technology called Film Pattern Retarder, developed by LG, where a polarizing film coating the TV screen allows each eye to view every other line. See #31 for our impressions.
At CES 2011, a system that claims to deliver full resolution yet allow the use of cheaper passive glasses. Products with this or similar technology won't be widely available in 2011, however.
No. Between 5 percent and 10 percent of Americans suffer from stereo blindness, according to the College of Optometrists in Vision Development. They often have good depth perception--which relies on more than just stereopsis--but cannot perceive the depth dimension of 3D video presentations. Some stereo-blind viewers can watch 3D material with no problem as long as they wear glasses; it simply appears as 2D to them. Others may experience headaches, eye fatigue or other problems. (See also .)
Viewing certain programming on a 3D TV can cause headaches or other ill effects in some viewers, especially over longer periods of time. In our experience, and in the opinions of most experts we've consulted, the main cause of headaches or eye fatigue isn't the 3D technology itself; it's badly produced 3D content.
Comfort is a major concern of most 3D producers. Too much of a 3D effect can become tiresome after a while, abrupt camera movement can be disorienting, and certain onscreen objects can appear blurry, for example. The best 3D movies, like "Avatar," tend to use depth effects that stay close to the plane of the screen, with fewer gotcha objects that pop out or recede into the screen excessively. Even so, comfort with 3D varies widely from viewer to viewer, and one recent study () found that older viewers can experience less discomfort than younger ones.
Content producers are still refining methods to deliver a comfortable experience that's still "3D enough" to satisfy viewers, and since 3D is still a relatively new medium. The best 3D is still found in theatrical productions, so if you're concerned about eye fatigue, we recommend seeing a 3D movie or two before investing in a 3D TV. We don't know of any definitive studies that indicate any long-term or permanent damage caused by viewing 3D, and by most accounts the more 3D you watch, the more comfortable with the effect you become.
To watch anything in 3D you'll need a 3D-compatible TV and a source capable of delivering 3D content to the television--most often a 3D Blu-ray player, but perhaps a cable or satellite box, game console or streaming video device. For some setups you'll want an AV receiver or home theater system that can switch HDMI 3D sources. On the other hand you'll most likely not need to buy any new HDMI cables. Oh yeah: you'll also need a pair of 3D glasses for every viewer.
3D content: movies, TV shows and games
Yes. With the exception of simulated 3D (see #18) you'll need specialized, new 3D content to watch 3D. The most common such content today takes the form of 3D Blu-ray discs, which first appeared in 2010, that adhere to a specific 3D standard and bear the 3D Blu-ray logo. TV shows and video games also need to be in a specific 3D format (see #20) to provide the 3D effect.
Very few. The first 3D Blu-ray to bear the logo above and be available for sale in stores was "Cloudy With a Chance of Meatballs." Since its release On June 22, 2010, a smattering of other titles have become available in stores and online; Blu-ray.com shows 39 U.S. titles available now, with another 21 announced to arrive before the end of the year. Many of them are documentaries, IMAX films or children's animation. Many, , are exclusives only available as part of a bundle when you buy a 3D TV or other gear. Other notable titles coming this year include "Tron: Legacy" (April), "The Green Hornet" and "Bolt" (2011). We expect the trickle to continue throughout 2011 along the same lines.
Many Blu-ray and DVD titles, such as "Coraline" and "Journey to the Center of the Earth," contain versions of the films, and often a couple pairs of colored glasses, in the old anaglyph style, and so cannot deliver full-color, high-resolution 3D (see #3). Even more confusing is that some titles, like "Coraline," are also available in the "new" 3D Blu-ray format (see #12. The best way to differentiate between the new ("full HD") and the old ("anaglyph") 3D Blu-ray discs is to look for the official 3D Blu-ray logo.
Not many. Aside from sports, no mainstream TV programming is produced in 3D, and no major networks aside from Discovery and ESPN have announced 3D channels.
The most widely-carried 3D channel is ESPN 3D, available on DirecTV, Comcast, AT&T U-verse and Time Warner cable. Itwith the World Cup soccer tournament and went to a 24-hour format on February 14, 2011. It shows some live events, such as the 2010 Home Run derby and a few college football and NBA games, but most of the content is prerecorded.
DirecTV also, the first 24-hour 3D channel and an exclusive venture with Panasonic, last year. It shows the occasional 3D event, such as the 2010 baseball All-Star game and US Open tennis tournament, as well as documentary fare.
On February 13, 2011, DirecTV began carrying, another 24-hour 3D channel from Discovery, IMAX and Sony that will specialize in nature and documentary programs. Unlike n3D it's not an exclusive, although no other carriers have picked it up as of press time.
Other cable and satellite providers offer the occasional event and/or have some 3D available on-demand, but currently DirecTV has the most 3D TV content by far.
Again, the pickings are slim. Among video game consoles the Sony PS3 supports the widest selection of games, including Gran Tourismo 5 and Call of Duty: Black Ops, and plans a full slate of 2011 releases including Killzone 3 and Uncharted 3 (full list). The Xbos 360 supports a few as well, including COD: BO and Batman: Arkham Asylum, but doesn't deliver nearly as many as the PS3. Nintendo's Wii doesn't have 3D games, but the company will launch the , a glasses-free portable gaming platform, in March 2011.
With the help of gear like the
With 3D slow to arrive to TV providers and Blu-ray disc, we expect Internet streaming services to help fill the 3D content gap. , delivering 3D movies in the side-by-side format (see #20) to select TVs and Blu-ray players, including the Sony PlayStation 3. Samsung offers a separate TV "App" with trailers for 3D movies. Netflix and Amazon Video-on-Demand don't offer 3D yet, but it's just a matter of time in our opinion before they, along with YouTube and other video services, join the club.
3D hardware: TVs
Yes. With one exception, no HDTVs can be upgraded to support the new 3D formats used by Blu-ray, DirecTV, the Sony PlayStation3 and others.
One reason is that the TV must be able to accept a 3D signal, which is basically two 1080p/24 images (one for each eye), to display Blu-ray 3D. That's potentially confusing because many non-3D LCDs have, and manufacturer marketing also mentions "600Hz" plasmas. Regardless of the "Hz" spec, these non-3D models can only handle a single-image source, not the double-image signal required for Blu-ray 3D.
Another reason is that 3D requires different video processing and additional hardware, including some way to send the necessary infrared or Bluetooth signal to the active 3D glasses. Passive 3D TVs use a special screen "retarder" (see #5) that's not standard equipment on 2D TVs. We're not ruling our the possibility of third-party add-ons overcoming these limitations, but as of now there's no way to convert any 2D TV to be compatible with the new 3D TV formats.
The exception mentioned above applies to the approximately 4 million 3D compatible rear-projection DLP and plasma TVs sold in the last few years by Mitsubishi and Samsung. Both companies sold such DLPs, and Samsung also sold the PNB450 (2009) and PNA450 (2008) series plasmas, but all of them required a special 3D kit, along with connection to a PC source, to display 3D. Mitsubishi now sells a conversion kit ($449 with two pair of glasses) that allows older Samsung and Mitsubishi 3D DLP TVs--but not older Samsung 3D plasmas--to work with the new 3D sources. Third-party sites also sell conversion kits that work with these legacy 3D TVs.
It depends on screen size, extra non-3D feature differences and many other factors, but in 2010 cost of a 3D versus a non-3D model was at least $200, and usually more. As of press time Panasonic's 50-inch
Comparisons like this aren't strictly apples-to-apples, however, and especially in 2011 3D TVs will come closer to their 2D counterparts in price. Nearlywill be 3D-capable, and we expect nearly all of the best-performing TVs to support 3D.
Yes. All 3D TVs will display current 2D content with no problem and no glasses required, and their 2D picture quality is not affected in any negative way we've noticed by their 3D capabilities. The Blu-ray 3D specification calls for all such discs to also include a 2D version of the movie, allowing current 2D players to play them with no problem.
Many 3D TVs include 2D-to-3D conversion processing that will allow viewers to "watch everything in 3D." However, in our experience those systems don't come close to the realism of true 3D content. Check out ourfor a taste.
In 2011 some Blu-ray player makers have announced units, llike the
That depends on the TV and its picture settings. We'veand a few, namely Panasonic and Samsung plasmas, draw significantly more juice in 3D mode at default Standard picture settings. On the other hand, the LED TVs we've tested draw just a bit more, and one LED model actually drew less.
Of course TV makers are free to adjust picture modes, which directly affect TV power consumption, and the Energy Star guidelines for TV power use do not apply to 3D mode. 3D TVs displaying 2D material don't inherently use more power than 2D TVs.
Unlike with see #16) . All new 3D TVs will handle all three formats, although you might have to manually engage the correct setting in the case of the latter two., there doesn't seem to be a major "format war" between the various methods for delivering 3D. Those methods include "frame packing" for Blu-ray (the only one to promise "full 1080p to each eye"), side-by-side and top-and-bottom for TV programming and most games (which both halve resolution), and "checkerboard" (used primarily by the older DLP models;
It's also worth noting that Blu-ray discs "exclusive" to one manufacturer (see #10) will play on every new 3D TV. Despite being a Panasonic exclusive for now, for example, the "Avatar" 3D Blu-ray will play on any current 3D Blu-ray player and/or TV.
3D hardware: Glasses
In 2010 only two TVs included active 3D glasses, the
We expect more of the same in 2011. Active 3D glasses will remain an optional ($60/pair and up) accessory for all but the highest-end HDTVs. Bundling glasses in with the TV for "free" will remain a selling point for passive models, all of which we expect to include at least 2 and more often 4 pairs.
No. Active 3D glasses are proprietary for each manufacturer, so for example if you have a Samsung 3D TV, only the Samsung active 3D glasses will work with it. Despite calls for a "universal" glasses standard, in 2011 we don't expect to see any active glasses work cross-brand. There are third-party universal 3D glasses available, however, such as the XpanD X103, that will work with any active 3D TV.
Passive 3D TVs, on the other hand, will work with most circular polarized 3D glasses regardless of brand, although some differences (slightly different tints, for example) may affect performance.
Yes. Every member of a family sitting around the 3D TV, for example, must wear the glasses to see the 3D effect. If they don't, the image on the screen will appear doubled, distorted, and, for most practical purposes, unwatchable. Currently, there's no technology that lets a single TV display both 2D and 3D content simultaneously without glasses.
Yes. People who wear normal prescription lenses already can experience the full effect by wearing the 3D glasses too, which are designed to fit over an existing pair of glasses. Of course it can be less comfortable to wear two pairs of glasses, and currently prescription 3D glasses are rare.
3D doesn't work when you lie down sideways on the couch, and passive models seem to lose the 3D effect as well when viewed from far off-angle (see #34).
On the other hand passive 3D glasses don't impede looking at your laptop, aside from darkening the image a bit. But when active shutter 3D glasses are turned on they strobe rapidly (see #5), causing the LCD screens of laptops, cell phones, iPads and similar devices to flicker to a greater or lesser extent. In many cases the flicker makes such screens unreadable. Active glasses also cause similar effects under some fluorescent lights, although the effect is usually subtle unless you look directly at the light.
Glasses-free, or autostereoscopic, 3D TVs have been released before, and are from Toshiba, but the technology is not ready for the mainstream. It's currently quite expensive, of limited screen size and requires viewers to sit in very specific places relative to the screen. Given these limitations we expect it to be a few years at least before autostereoscopic TVs hit U.S. stores in any quantity. Of course, we could be wrong.
Other 3D TV hardware
With one huge exception the answer for Blu-ray players is "yes." No Blu-ray player maker has said it will upgrade existing 2009 or earlier standalone players to work with Blu-ray 3D movies, so a new 3D-compatible Blu-ray player will be required for many viewers to view the new 3D Blu-rays.
The Sony PS3 is the huge exception. Sony released a free update in September 2010 that allows its game console to play 3D Blu-rays. it works fine, as does the functionality.
A few 3D games are available for the Xbox 360, but it's not a major focus for Microsoft the way it is for Sony. As far as we know there are no 3D games for the Nintendo Wii.
Many current DVRs, satellite and cable boxes will allow you to view 3D TV shows, although all use the lower-resolution "side-by-side" format (see #20). Check with your provider to determine 3D programming availability.
Unless you use your AV receiver for switching between HDMI video sources, you won't have to upgrade to enjoy 3D Blu-ray movies. You could get a 3D Blu-ray player with dual-HDMI outputs, such as the
Yes. In our lab we've sent 3D Blu-ray signals through numerous varieties of HDMI cable, including inexpensive ones, and all have worked fine. That's because .
There has been some confusion over whether certification in the newest HDMI standards, namely, "high-speed,"or , is required for cables, TVs or other AV gear to properly handle 3D. The answer in our experience is "no." In short, HDMI specification is a messy business. Being HDMI 1.4 certified doesn't mean that certain features of the new specification, such as 3D, higher-than-1080p resolution and a new Ethernet channel, are necessarily included on a given piece of hardware. Our best advice is to ignore the HDMI version of a particular product and focus on actual features provided in manufacturer product information.
2010 saw a smattering of still cameras and camcorders that can produce 3D photos and video (see the slideshow below for reviews and notes), and this year even more will arrive. The 2011 camcorders announced so far, with the exception of, "targeted prosumers and experimental indies; that is, gadget hounds with deep pockets and pros looking for relatively inexpensive (for them) models to start experimenting with" according to our . New 3D camera announcements were relatively slim, aside from a couple and Olympus models, but as 2011 rolls on we expect more 3D cameras to appear.
CNET's reviews and opinions on 3D TV
Most of the Best HDTVs we've reviewed include 3D capability, and we evaluate their performance in a special section at the end of the review. We've also created a six-way comparison that summarizes many of those performance findings so far. You can also sort our TV database by "3D-ready" to find both reviewed and unreviewed models, or scope our main 3D TV resource guide for more articles. Expect all of these resources to be updated throughout 2011.
For other 3D gear, we first recommend our Best Blu-ray players list for 3D-compatible devices, although notably we haven't seen much difference in 3D picture quality. The same statements apply to our Best AV receivers, although current 3D Blu-ray home theater systems are rare. See #29 for 3D camera and camcorder reviews.
One 3D TV product category we haven't publisged any reviews for is. While we certainly think projection is an ideal venue for 3D, other categories are currently higher-priority for our reviews team.
In our brief experience so far, we preferred the active 3D experience since it delivered full resolution without the jaggy artifacts we saw resulting from the every-other-line method. Check out ourfor more, including our current testing-based opinions on the advantages and disadvantages of each system. We expect this opinion to evolve as we test more passive displays.
Based on our reviews of 2010 models, plasma has a clear performance advantage over LCD. Plasmas we've reviewed have significantly less crosstalk (see #33), and also exhibit superior black levels in general compared to most 3D LCD TVs, all of which use LED backlighting. We wouldn't be surprised to see this performance gap narrow in 2011, however.
As of press time we haven't reviewed any newer rear-projection 3D TVs, all of which are made by Mitsubishi and use DLP technology.
Crosstalk, sometimes referred to as "ghosting," is our least favorite 3D-specific picture quality issue, and has been present to a certain extent in every 3D TV we've reviewed. Visible crosstalk is caused when the both images on the screen--which should be alternately obscured by the glasses so you see only one unified 3D image--are visible at once to some degree. Another way to think about it: 100% crosstalk is where you're not wearing glasses at all.
The main cause of crosstalk in our experience is the content. Some images, for example bright objects on a dark background or vice-versa, are show the doubling on nearly all 3D TVs. LCD TVs also seem more crosstalk-prone than plasmas (see #32). Finally, the 3D glasses, whether active or passive, also apparently have an effect.
For a more thorough, albeit technical, discussion of crosstalk, this 2010 research paper provides a good starting point.
Aside from potential viewer fatigue issues (see #7), crosstalk (#33) and the resolution loss in current passive systems (#5), we've observed a few picture-quality differences between standard 2D and the new 3D system.
Since both active and passive glasses block light greater or lesser extent, the same image on a 2D TV will appear darker to the viewer than that of a 3D TV. Because we do our testing in a relatively dark room we don't mention this issue much and don't consider it a big deal for critical viewing, but if you prefer a brighter image, then it might become a problem. Most LCD TVs, especially at larger screen sizes, can get brighter than plasmas, and passive glasses allow significantly more light through than active ones.
Different 3D glasses may also have different color characteristics; for example Panasonic's active glasses have a pronounced amber tint. TV makers compensate by creating "offsets" in the TV itself that apply when a viewer engages 3D mode. They mostly work well, but careful observers can detect color inaccuracies between 2D and 3D. The tint in active glasses can also color the crosstalk, making it even more noticeable.
Viewing an active 3D TV from off-angle, either from the side or above or below, is generally the same as with 2D, and the 3D effect is preserved. Passive TVs, however, seem to lose the 3D effect more rapidly.
We have also observed that horizontal movement, for example camera pans, can appear choppier or more prone to judder than in in 2D (some TVs have smoothing processing in 3D designed to combat this effect). As we mentioned above (see #4, the edges of the screen in 3D become much more noticeable than in 2D; depending on the content, the image seems to "fall off" abruptly along the screen edge where the image ends and the rest of your field of vision begins. One effective way to address this issue is to sit closer ( ) or view a larger screen.
High-quality 3D content seen seen on any new 3D TV can be very impressive and definitely delivers a "wow" factor that will appeal to fans of immersive home theater, gamers, and other early adopters. Aside from screen size, the experience is very similar to what you'll see at the theater.
On the other hand, judging from initial reactions, 3D TV is a lot more controversial than, say, 2D HDTV. Many viewers of 3D come away less-than-impressed, complaining of headaches, visual artifacts or otherwise unnatural-seeming images. We've seen plenty of those ourselves, and even experienced some, in a year of 3D TV reviews.
That said, we think 3D TV is here to stay, and will improve rapidly like any new technology. The biggest gains, frankly, need to be made on the content production side. We consider "good" 3D content (think "Avatar") the most important factor in whether 3D is enjoyable to any given individual. Another important factor in our book is amount of experience someone has in actually watching 3D. In general the more 3D hours a viewer logs watching good content, the more used to the 3D effect he or she becomes, heightening the possibility of immersion.
Finally, when evaluating whether 3D TV is "any good," it's worth drawing attention again to the many issues described above and.
And of course, like any new technology (or product for that matter), 3D is in essence intended to get you to buy more stuff. Years of underwhelming 3D implementations and misguided marketing earns 3D more of a right than other technologies to bear the description "gimmick." Again, we recommend seeing 3D in the theater, or better yet visiting an electronics store and seeing a 3D TV demo yourself, before writing 3D off or becoming a fanboy/girl.
Even after seeing an impressive in-store demo (check out the video above), it pays to consider how the technology would be used in your home, if at all. 3D isn't for everyone, and we don't believe 3D TV is appropriate for all content types--if only because viewers will be reluctant to don glasses to watch the evening news.
Definitely not. Especially for smaller and/or low-end TV purchases, 3D capability is unnecessary.
If you're buying a larger model and/or shopping at the middle-to high-end of TV makers' product lines, however, 3D may be an inevitable feature. In 2011 most such TVs will be "3D-ready," meaning that they don't include active glasses (see #5) but will display 3D given the right gear and content (see #8). More importantly, it will be difficult to find such TVs that don't do 3D, and some makers, like Vizio with its passive models, have announced 3D models at relatively low price points in their lineups.
Our best advice, which applies to the 3D feature more than to any 2D step-up feature, is still to see for yourself. If you've narrowed it down to two similar models you can afford, one with 3D and one without, we do think it's definitely worth seeing 3D TV in action before making your decision. TVs last a long time, 3D content will become increasingly common, and we don't anticipate competitive "glasses-free 3D" (see #26) hitting the market anytime soon.
So there you have it: the basics of what we know about 3D TV today. We'll be reviewing new models throughout 2011 and hopefully updating this FAQ more than once per year (ha!). In the meantime feel free to add a comment.