Here's a long list of what you need to consider:
1.) You said you only want the TV to last 4 or 5 years. You need to ask yourself if that is *really* what your intention is, or will this tv likely remain in your household for much longer? Most people have televisions that last 10 years or longer and are quite happy with them. So, again, is 4 or 5 years a real assessment? If it is, get a good 720p set and save your money. IF the tv will be around for 5 to 10 years, consider spending on a good 1080p set.
2.) Standard tv is scheduled to be replaced entirely by HD in Feb. 2009 -- well within the useful life of this tv. Also, HD tv standard is either 720p or 1080i, I have not seen any broadcast commitment to 1080p due to broadcast bandwidth issues. It will likely be a very expensive proposition for tv broadcasters to commit to a 1080p standard if it will cost them more money to broadcast in native 1080p, so I wouldn't hold my breath!
3.)If you are really committed to buying 1080p, make sure the set can display a 1080p signal, NATIVELY. As you may have noticed from several other reviews, many sets display in 1080p by upconverting either a 1080i or 720p picture. This is a major reason for a grainy or subpar picture on tvs that alledge that they are "true" 1080p. Even if the set has an HDMI interface, the signal may be being upconverted from 1080i to 1080p as there are very few devices that actually broadcast a 1080p signal. Currently, the only device that I know of that has the capability of supplying a 1080p signal to a tv is the new Sony Playstation 3. (Both models provide a true 1080p signal via HDMI.) To take a minute and clarify here, the tv *should* be able to display a 1080p signal natively since future devices will likely have the capability to supply a native 1080p signal.
4.) Three HDMI inputs only matters if you will have 3 devices hooked up to the tv that an HDMI connection provide add-value to you. The 3 devices to consider are: DVD/DVR player/recorder, Cable/Satelite box/DVR, and a game system like PS3 or Xbox360. Also consider whether you intend to buy any of these devices in the next 4 or 5 years, during the supposed time you expect to own the tv! (If not, then 2 HDMI connections are probably enough.)
5.)Something else to consider is that regular DVD's broadcast in 480p, so any benefit to buying an upconvert DVD player/recorder with HDMI connection is really a waste of money if the TV also has upconvert capability. My recommendation is to use a DVD player with it's component inputs and let the TV do all the upconversion, instead of wasting money of an upconverting DVD player that will upconvert the signal from 480p to something higher (720p or 1080i) and then have your tv modify that signal once again to 1080p! A good 1080p tv will do a good job of upconverting the 480p signal to 1080p, via the TV's internal signal processor. Also, my opinion is that the tv's processor will probably do a better job of upconversion since it is "matched" and built into the tv (vs. an upconverted signal from a dvd player that is independent of any tv it will play on.) A good way to look at this is upconverting DVD players/recorders/devices are only good for HD-Ready tv's and tv monitors since they lack the internal processor to do any upconversion on their own. A full-HD tv already has a processor built in for handling this task...The real question is, how *well* does the internal processor handle the task?!
6.) Don't get hung up on the new HDMI standard. It deals with bi-directional communication along the connection and only really matters with hooking HDMI up to an audio component system. The TV will not likely benefit from the HDMI v1.3 standard nearly as much as, say, a surround sound receiver will. I won't bore you with the details about what HDMI v1.3 is supposed to do, but that's the deal with the next version of the HDMI standard. It benefits audio way more than video. I will mention, however, that the new standard is backwards compatible, so don't worry about losing any current HDMI support.
7.)Lastly consider whether you want to ride the technology wave. If you buy latest-and-greatest now, it is likely to still be a fairly competent tv 5 to 10 years from now! Sure there will always be something better, but that's the nature of the industry! You waited this long to get into HD for several reasons that were all practical and good decisions, I'm sure, but there are always 2 decisions to make when it comes to buying technology: do I spend more money and get something that will last over the long haul, or do I save some dough and buy something that is competent by today's standards, but may be outdated in a few years? If 4-5 years is all you will have this tv, spending more money for 1080p may not be worth it depending on how you feel about the other things I pointed out. If the tv is *really* going to be around your household for 5-10 years, then strongly consider the 1080p solution with 3 HDMI connections. You will probably be happy over the long haul.