I assume you mean a "flat panel" as opposed to a "flat screen". Flat screen picture tubes have been around for about a decade, and you can get wide screen version of those tubes within your price range. You can easily get a 32"+ flat panel within your price range, but it could be too wide for your armiore.

First, you may ned to decide what you are going to do with it before you choose Plasma, DLP or LCD. If you are going to have HD, use it as a computer monitor or gaming might make a difference into what you are looking for. You are probably going to want HD, either through satellite or cable, so you may want to research HD as well.

Here are two links to start with, since I really didn't help.

http://www.flattvpeople.com/tutorials/lcd-vs-plasma.asp
http://www.lcdtvbuyingguide.com/lcdtv-plasmavslcd.shtml
(Don't worry about the 2nd one, since you can access the same comparison by using www.plasmatvbuyingguide.com)