It looks like a plasma should work out fine. What would really kill it is a light source directly behind your viewing position, which reflects light off the screen and directly at you. Light sources at a sharp angle won't be a big problem. But it also depends on the TV. My ST50 does great in a bright room, but others may be too dim.
And regardless of your TV type, you absolutely need some curtains over that backdrop! Having a bright window directly behind your display device can totally ruin the experience, particularly if it's a dimmer set like a DLP. Your pupils constrict because of the bright background, and darker details on your screen disappear.