I think it's worth it personally. There is so much rage over the device, mainly from people who have either never used it, don't like gesture games, or think it's cool to bash it, that I think many things get skewed. I actually work in the professional mocap world, like the big camera systems with dudes covered in ping pong balls, and the quality of tracking, and technology in it, is effectively what a company in the industry sells for $50k. MS got the launch price down to $150, which was insane to me. You see it in the Kinect Hacks that are out there.
So the tech is unbelieavable, how does it work? That's up to the devs. There are some very clever ways to design around it (Child of Eden, Gunstringer, Haunt) then there are some really bad ways (Rise of Nightmares, to a degree Kinect Disneyland). My first "oh shit" moment was watching my kid play Kinectimals. He was playing, sneezed, then a second later his tiger sneezed. Wha? The interactivity for it is exceptional, it's more accessible (why do people bash this aspect...if it's not for you, great, but why pretend like there isn't a market for it), the audio component is very impressive, and for those who want to have an active experience while playing games, it's an astounding device.
Check out some games, if you have kids I consider it a must-buy, but if you couldn't tell yet by my long post, I think Kinect is very much worth it. I bought in at $100 at launch and haven't regretted it for a second.
Edit: Oh, and the games I have:
Sesame Street Once Upon a Monster (very good, 6yr old loves it)
Rayman Raving Rabbids (got it really cheap, just OK. 3yr old likes some minigames, doesn't like others)
Happy Action Theater (tons of fun)
Kinect Sports Season 1 (most sports are really, really well done)
Dance Central (I don't like it, but my wife did)
Kinectimals (very cute, fun to watch my kids play)
Child of Eden (hard, but tons of fun, immersive, good game)
Kinect Disneyland (minigames were fun, walking around the park, not so much)
UFC Trainer (mostly good, but incredibly frustrating when trying to do pushups and not have them registered)
Kinect Adventures (the pack in game-not terrible really)
Haunt (XBLA game that is lots of fun, funny. Nice surprise)