Too be honest I do not own neither Xbox 360 nor Kinect. But I tried it when a friend of mine showed it to me. I really have to say that I'm pretty impressed what the technology does so far but I'm really disappointed in the Games. But to be fair: Kinect just came out. There will be better games when the time goes by for sure.
Back then when I played PC Games I found Alien Arena to be a pretty good Shooter. Of course it's not near comparable to nowadays standard.
I guess 1 in 30 UK Prisoners have a Cell in their Games Console.
GoW all the way. I am still amazed how they could make an even better Game than GoW2. One of the best games I ever played. And the most bad ass voice acting since The Darkness.