The xbox kinect looks really cool, and gets some great reviews (check out Amazon and look up xbox reviews-you'll get some good links). My girls want a Wii for Christmas and in checking it out, we learned about the xbox kinect. I love that no controllers are needed, the games seem really fun and it would be a blast. If the system works for you, I'd say go for it. It does have one main drawback that for many might be insurmountable.
The main drawback for the xbox kinect is you need a lot of space in front of your tv for the sensor to work. A good 8-10 feet or more. The sensor won't "sense" you if your room is small. Or it might only be able to "sense" one person, but not the other players. Since a good many games are multiplayer, this is important. Other considerations for this system: the lighting in the room matters-being lit from the front is best, back lighting is not so good. That's a fixable thing I would imagine, but something to consider. And the other thing is to stream netflix you do have to have the xbox live account. The account costs $ but I'm not sure how much.
So, overall I'd say the xbox/kinect system is ideal for anyone considering a gaming system if they have the space for the system to work correctly.
If we had the space I'm not sure which system we would have gone with. However, our room is fairly small so we are getting the Wii.