make sure it is a hdcp compliant television or it might not play so nice with your ps3.
don't buy a 720p, get a 1080p.
you don't need led backlit. at that price range its not going to be an improvement.
go with lcd, don't go with plasma.
get one with the inputs you need.
i've had good luck with my sony, but i'm sure other brands are good as well.
go to a local store, look at the prices, look at how they appear (keep in mind they crank the brightness/colors WAY up) and then go home and read reviews on the models you liked most. visit newegg/other stores and read actual buyer comments. this should get you a good idea of how the product will perform.