also what will you be watching? That helps decide what you will buy. Also, don't fall for the flat panel hang on your wall hype - get what looks best to you whether it's DLP based or if it's LCD or Plasma. I have a 55" Sony LCoS and I love it. If you go LCD, check out the Sharp 52"
AQUOS widescreen lcd television | LC-52D62U
My buddy got one and it looks phenomenal.
I disagree with Blong, you want to buy 1080P, if your current TV is 12 years old, chances are you will keep this one for awhile. So buy the most current technology because it will get the most mileage, longer.