What makes a good HDTV?
We all want the best TV we can afford. But what makes a TV "the best"?
A TV is a big purchase, and we all want to get the best TV for our dollar. But what makes an HDTV the best? If you spend more, are you guaranteed a better TV? With all the jargon, marketing, and hype, what performance and features matter the most?
Well, I'm glad you asked.
There are three main factors that determine how "good" a TV is. "Good" is clearly subjective in this case, which is why weighing the importance of the following factors is up to you.
Picture quality
When I sold TVs, I'd ask what people were looking for in their potential purchase. It was really just for my own amusement, because without fail people would say, "Good picture quality."
When pressed, though, most people couldn't elaborate on what constituted picture quality in their view.
Contrast ratio
One of the most visible aspects of picture quality is contrast ratio. This is the difference between the darkest a TV can be and the brightest.
A high contrast ratio gives the image dimensionality, makes it "pop." Everyone wants high contrast, but as I explained in another article, it's hard to judge which TVs have a good contrast ratio.
Color
Personally, I'm a fan of accurate color. At first glance, this seems like a given, but many people prefer slightly oversaturated colors. In fact, most TVs when taken out of the box present oversaturated colors. What's important to me, in finding our dream TV, is the ability to adjust the colors. Most new TVs have modes in which you can choose between oversaturated and reasonably accurate color. Samsung LCDs often have very accurate color, as do TVs certified by THX (at least in their THX mode). Most newer Panasonic plasmas have accurate color as well. Thankfully, almost all modern televisions have adjustable color temperature, so this isn't the factor it once was.
Scaling/deinterlacing
More and more, the scaling or upconverting performance of a TV is becoming irrelevant. Most new televisions are sent a 1080i signal, either from a Blu-ray player or a cable/satellite box. So the TV's performance in this regard doesn't matter. Almost all TVs deinterlace correctly these days, so this isn't much of an issue, either.
One might class overall light output, or how bright a TV is, under the heading of picture quality, but I disagree. Bright TVs are great, but it's easy for a relatively "dim" TV to have vastly better picture quality than an extremely bright TV. An easy example of this is Pioneer's old Kuro plasmas compared with many of the new LED LCD TVs. Side by side, a Kuro would be lucky if it could produce one-third of the light of an LED LCD. Subjectively, if the two TVs were judged on their own for picture quality, the Kuro would win easily.
Features
Most modern TVs do at least a decent job of creating an image. Some, of course, do a better job than others, but it's rare to find a "bad" television. (At least, from the name brands. If you're buying an LCD out of the back of a white van, your mileage may vary.)
So it's features that are the biggest differences between TVs.
Netflix and other streaming services
Netflix has gotten huge in the last year, and rightly so. Tons of streaming content, all for a low monthly fee. The question is, do you need Netflix streaming to come with your TV? If your Blu-ray player doesn't have streaming built in, then sure, get it in your new TV. Trust me, you'll love it.
If you don't have a Blu-ray player, well, you should get one. They're crazy cheap, and offer better scaling than most TVs. Even some of the cheapest models (under $100) have built-in streaming. So if you're going to get a Blu-ray player, don't worry about whether your TV does streaming or not. 
3D
3D is a huge push right now, mostly because of the premiums it's possible to charge at the theater and for 3D TVs. I'm pretty apathetic about the whole thing, but if you're into it, go for it. The most important thing to realize about 3D is that it is just a feature. You don't have to use it.
Most high-end models happen to have the ability to show 3D. Because they're high end, they also typically look the best as well. Personally, looking for the "best" TV, I'd end up looking at 3D models, even though the 3D aspect is irrelevant to me, because of how well they show 2D.
Light and lighting: The TV vs. your room
Here's where light output comes in. In finding the best TV, it's best to ignore hype and marketing and just ask yourself how you'll use the TV. In a dark room, or at night, plasma offers the best picture quality. Plasma TVs aren't "dim," but in a brightly lit room, they're not going to look as good as one of the new LED LCDs, which often have prodigious light output. For daytime viewing, LCDs still edge out plasmas, despite the antireflective and antiglare coatings.
Related links
• "="" rel="follow" target="_self">CNET's HDTV Buying Guide
• Should you upgrade your home theater gear?
• More TV-related blog posts
That said, a plasma is still plenty watchable during the day, and an LCD (with an adjustable backlight, anyway) will still work fine in a dark room or at night.
Price
Tally up what you've picked as important for your future TV. For me, I've focused on a TV with a decent contrast ratio, accurate (or adjustable) color, possibly streaming, possibly 3D, and probably a plasma, as I do most of my TV watching at night.
Finding a TV that matches all of your criteria is only half the battle, of course. The other half is the price. Price has a pretty direct relationship to the one thing we haven't talked about:
Size
Small TVs are cheap, big TVs are expensive. That much is generally true. There are plenty of guides that tell you what size TV you should get, but to be honest, I've yet to hear of anyone who actually follows them. Most people buy a TV in the 42- to 50-inch range because they think it looks right, and because it's affordable.
The truth is, you can go much bigger if you want. I sit 10 feet from a 102-inch screen, and it's epic. You don't need to go that big, but you can if you want to.
It's a tough call between a good TV that's big, and a great TV that's small. I'd generally err on the side of larger, but really this is something that's best judged on a case-by-case basis.