Always get projectors!!!!
Anyway, a couple of things to take note. Your black levels will be better on the Panny unless you spring for a good Epson or JVC. You can find used ones from both manufactureres in your price range. Look up the JVC RS1, RS2 and HD100, and Epson 6500UB, 8500UB on Videogon. There's a couple up there for <$1000 with new bulbs. Sharpness will be better on the plasma unless you get a good DLP like BenQ's.
What size screen do you want? You haven't really given us enough information to recommend a projector. Projectors suffer greatly from ambient light where TV's don't. The fact that your room is dim helps, but if you can get it completely black that would be ideal.
Bottom line, yes you should get a projector. They are exponentially more immersive and awing than little TV's.