I have COD-Black Ops, Battliefield Bad Company 2, Halo Reach, and i am looking forward to arkham City as well. Recently got Test Drive Unlimited 2 but i also play Rock Band, Guitar Hero games. Most often i am watching netflix on my 360 though.
More the merrier.
I never got a 360 but if i did i would be playing Disgaea 3. One of the best videogame series i have ever played.