The best TV's now on the market are the Samsung tv's. Depends on how much you have to spend but if I were you I definitely would take the UE46E8000 or 9000.
4K TVs are now 999$ from Vizio/Polaroid http://www.gizmag.com/50-inch-4k-television-polaroid-vizio-ces/30402/ Better than any black friday deals!! I wonder how long these will last though.
Get a LCD or LED never get a plasma. Plasma is cheaper but they wont last as long and you with start to get burned in images after a while. Samsung and Sharp are my favs but LG has this new curved tv that looks interesting.