All I know is the best deal for this stuff is on Slickdeals.com Just scan their posts for one...thats how I got my sweet new 42" LCD for $600 Slickdeals.com Best site for deals on ANYTHING!
It's all about the hertz of the tv. The refresh rate if you will. If you get a plasma make sure you get a 600 hertz over the 480 hertz. If you get an LCD then make sure you get 120 hertz over the 60 hertz. As for the two technologies, I would go LCD. Plasma will start to get dimmer over time, and plasma tv's reflect light a lot more than LCD sets. I have both, and a projector in my media room and the regular 60'' tv's are both fine. But I can totally see the difference between the old flat screens I gave to the kids, and the new ones. If you have the room for it, I highy recomend getting a projector. Mine goes from 60" to about 200" and is wonderful for viewing anything. It's great for gaming as well.
In order for a projector to look good, doesnt the room have to be pretty dark? We have a large window in our living room so there is lots of light in the room during the day.
It should. If you have a large window that sheds light, you have answered your own question. LCD tv's don't have near the glare that plasma's do. Just make sure you buy a 120 hertz.
^ I have a couple of Samsung LCD's and they are great. I don't think you can go wrong with Sharp or Samsung as long as you try and buy at least the mid-range model.