All I can say is, "lol kinect."
I still think Microsoft's strategy is to try and sell this thing as an all-in-one home entertainment thing, not just a game system, and they'll probably offer differing models at a couple different price points in order to try and gain traction in the market quickly. A combination of the PS3 approach (loads of new, unique features) and the Nintendo approach (lean on your fanbase for early adoption and word-of-mouth marketing).