i was recently in the market for a 50" and i ended up going for an LG 8000 (i think that is the model). it cost me €770 including a nice stand after some haggling and looking around.
Fantastic HD and size really impressive movies and HD tv, one thing i will say however there is a issue with image burn i.e pause a dvd for over 5 minutes, it sticks to the screen but does go but can be a little annoying. This is common on plasma TV's of this size, but this doesn't happen on LCD (hence the substantial price difference)
I had a look at Pansasion 50" plasma tv's, and they are great. Panasonic seem to be setting the standard, but my LG is also very impressive but a good €300 cheaper.
if you are not worried about image burn go for it, once you have a huge tv you wont look back.
Ohh by the way my brother has a HD projector and is nice but has a massive problem with colour dentisitve, i.e if any sunlight hits the projected screen you can barely see the picture. the projecter is much cheaper to buy i.e €400 + €100 for screen, BUT the load up time is longer, more difficult and time consuming to get it to work properly and doesn't look as impressive.
hope this has been of use
Alex