$200 for a new 4GB internal flash New Xbox 360, or $300 for a bundle with the 4GB Xbox and the Kinect (and Kinect Adventures). European prices are as always higher.
Kinect is two player standing room only, of course... and quite a bit more expensive than Wii. Does it really have a chance of competing?
I don't think so either. Too expensive, too restrictive, too casual centric; the hardcore won't buy it because there are no hardcore games for it, but Microsoft's current audience is mostly core and younger male "casuals" (ie people who only play sports games and FPSes; I don't know if I'd call such people "core"...). They won't get those people with this. But at that price, they won't get enough of the Wii market either. It really doesn't make much sense. But of course, if Microsoft has done one thing with the 360, it is consistently price many things too high...
Oh, the one good thing (for its chances) I can say is that at least some Kinect games will be $50 instead of $60, so at least they are competing at least partially with the Wii on price... not that that'll help them much.
It's actually more expensive for a full Playstation Move setup (four remotes, two navigation controllers, camera) than Kinect, but because you don't need to buy it all at once, it doesn't look as bad -- just like a reversal of the PS3 vs. the 360 early on, when the PS3 cost a lot more, but the 360 caught up once you bought some of the addons that the PS3 included for no extra cost... and people mostly look at the single sticker price, not the theoretical maximum amount it'll cost for a full setup, if they even want that.