A note that no one has mentioned:
$100 says that the Xbox 360 slim that has been rumored for quite some time (the one that uses one wafer for the GPU/CPU) launches with NATAL capabilities. Way to lower the price, launch a new Xbox 360, and re-market the 4-5 year old system.
I agree with Avinash that the average consumer won't buy NATAL at $200. That's why Microsoft will sell it for $70 or throw it in with a Slim 360 at $199.99-$249.99.
Back from the dead, I'm afraid.