I'd buy a Wii again, it's the proven default motion console. The other add-ons still have to prove themselves.
Never the less I would be interested in buying Kinect and use it for my MCPC if it works good enough, I read that Microsoft was going to make it available for Windows. Controlling my media from the sofa sans controller is a dream come true, I would no longer use my Wii Remote as a mouse.







