TV's are perfectly acceptable if you aren't a highly competitive player. I game mostly single player games and I don't notice any input lag with my TV so its perfect. I have a powered usb port right by my couch and a nice wooden surface that I use my mouse from with my keyboard in lap.
Best part about gaming on a 46 inch tv? A real home theater surround sound system. To me it sets it apart so much that when I have to use headphones I'm saddened. And I'm not talking about those home theater in a boxes, I'm talking a real receiver with passive floorstanding and bookshelf speakers with a powered sub right behind the couch.