Stay away from RCA. Complete garbage in my opinion. There are decent "cheaper brands" out there, but I think you're better off spending a bit more on a Sony, Panasonic, Sharp, LG, etc...
...and size is not as important as picture quality. I'd rather have a 32" Sony 1080p than some 50" piece of garbage. You can still find great deals on the good ones if you look hard enough.