Plasmas going to have a good picture, but they're hot and pull a lot of juice. Warmed up the room I had mine in pretty good...I had to add a small window air conditioner in the summer, but then again its a bit warmer here.
My advice is to go to costco, look at all the screens, see which one makes you happy (some people LIKE attributes that videophiles do not). Check them in-store for any fans they use...the warehouses are loud and you might not hear it there but will hear it at home. Fans drive some people nutty. I dont care.
Dont be too brand centric. A lot of screens use the same glass with different electronics and remotes. Some of the electronics are important though. If you're going to watch non-hdtv content or 4:3 content...see what that looks like on the screen you like. Some do a weird or crappy job of upscaling hdtv and stretching 4:3 content. For example, my old plasma looked great with a dvd but lousy with satellite or cable non-hdtv. I bought a cheap scaler for it (viewsonic vb50) and that was a lot better. It also stretched the whole picture, making everyone look like fat headed chubs. The DLP set I have now stretches just the edges of the material on each side, so the center half of the picture isnt distorted. It looks weird when something/someone moves from one edge of the screen to the other, but in 90% of the cases where the action or subject is centered and static, it looks very good.
Seems like you can sometimes get a better deal outside of costco or sams club, but I'd recommend paying a little premium to them so you can return it anytime. A lot of people get buyers remorse when they get the set home and see it in their setting, with their lighting, and their content. A lot of these sets are still of indeterminate reliability and longevity. I'd hate to pay two or three grand for something and have it go belly up a month out of warranty.
Best deals I can get is on sams club returns. My club sells their returns as used goods from the floor, marking them down every week or so until someone buys them. The vast majority are buyers remorse returns or people who stuck the thing on the wrong video connection or screwed up the setup and couldnt get a picture. Something ridiculous percentage of televisions are returned because they're so complex people dont know how to set them up.
I bought a big DLP set for $500 off because whoever tried to assemble the stand screwed it up a little. Some glue and a screw and it was easily fixed. The box with the actual tv in it had never been opened.
I got a 32" LCD set for $499 (from $999) because whoever bought it said "the screen is black and no sound", repair ticket said "set to demo mode" or somesuch. Remote and batteries were still in the original sealed bag with the owners manual.