Ok.
You have stated that you want to spend 500-600 dollars.
You have stated that you want to sit 6 feet away, and that it is in a bedroom.
You are visiting this site, so you want the best value for your dollar, and have done the right thing by coming to the internet, before a retailer.
So.
You should find a hdtv that is between 36-42".
At that size, the difference between 720p and 1080p is negliable. So don't worry about 1080p. You also don't have the budget for one. (I don't either, don't take it as an insult).
You should read up on all the different technologies and general hdtv information. Spend atleast 2 weeks just reading everything you can from various websites.
IGN has a really good regular feature, just go to gear.ign.com.
I would recommend narrowing down a few tv's that you want and just look for a deal at fatwallet, or the weekly ads.