In a room that gets a lot of natural light, I would say go with a plasma. At a viewing distance of 10 feet, a 42" should suffice and a 50" will give a bit of a wow factor. In the realm of plasma, Pioneer is one of the best for the most part.
Several other things to maybe consider:
1) How often will you be using the television?
2) What will you be primarily watching (movies, cable, sat)?