A Gamecube once fell off a shelf and hit me in the head. To this day I still keep it imprisoned in a larger cube made of plastic which I store in a metal rectangle.
And to answer your question stora, It really depends on what games your into and how long you want to wait for them. Xbox's kinect system has received fantastic reviews and has the main advantage of not requiring a controller to play. However, it fairly new, and more difficult to create a game with. This means that at the moment, the kinect game selection is quite small. However with time, more and more games will be released. The wii offers a more traditional method, with the motion sensing controller. The main benefit is that there is much more selection of games, including some classics that are only available for the Wii. Another thing to consider is that the latest Nintendo console (I don't recall the name) is rumored to be unveiled sometime this year.
Seth