Well, first off: I think you are in the wrong forum for TV advice.
Anyway, make sure whatever you gets has 1080P resolution (1920x1080) if you are even going to think about using it for your PC. LCDs are probably not going to fit in your size/price range for 1080P. Here's an LCD under 3,000 that supports 1080P:
http://www.newegg.com/Product/Product.asp?Item=N82E16889101094
Here are some DLPs:
http://www.newegg.com/Product/ProductList.asp?Submit=ENE&N=2102640487+1287417600+1251016243&Subcategory=487&description=&Ntk=&srchInDesc=
You can get bigger DLP for the $, but I prefer LCD (and from what I've heard, DLP is on it's way out soon anyway to be replaced by LCD).
Anyway, I'm no TV expert (obviously) but that's what I would look for in a TV if you are using it for a monitor. 720P is not going to be very good for PC use.