You'll find lots of information (and opinions) in the Home Theater Spot Forums
About a year and a half ago I finally bit the bullet and upgraded the 19" TV we'd been watching for years to a 50" Toshiba RPTV (Rear Projection TV). WOW! I love my RPTV!
The stretch mode on my Toshiba is great. Keep in mind that any decent large HDTV capable unit is going to be wide screen, so when you watch regular TV shows, the stretch modes are key. Otherwise you have to watch them with wide grey bars on each side of the picture.
I originally was looking at a tube type direct view TV (38" RCA I believe) but finally ruled it out because of issues like the fact that it made a small amount of noise even when it was turned off and because of all the glass in the picture tube it weighed a ton!
After discarding the tube TV, I started looking at 42" RPTVs. Then at one store they had the 42" next to a 50". The 50" wasn't that much bigger overall, but WOW, what a difference in the visuals! Plus the 50" had a fairly wide top on it for the center speaker, while the 42" would have required some kind of shelving.
The RPTV is on wheels so I can roll it around if I need to and it has plenty of inputs for antenna, cable/satellite, HD, DVD, etc. The room I have it in is about 12x15. The TV and the baby grand are at the open end and the seating is at the other. Not ideal because I have to use surrounds up near the ceiling for my front speakers, but with the new piano, I didn't have much choice.
Unless you keep your room dark all the time, rule out a direct projection with screen. Any significant light will wash out the projected image on the screen. Plus the bulbs are horrendously expensive!
Plasmas are ok, but they're still cost way too much for my budget. You can buy a 50" RPTV easily for under $2,000.