The Wii already has Just Dance which doesn't require a DDR controller.

A mid-console peripheral is not going to take down the Wii. That is just wishful thinking.

Kinect is rumored to be $120, but the price has not been officially announced yet. There also was no Kinect 360 bundle.

$120 is a lot to fork out-- Kinect's launch line-up looks like a carbon copy of the Wii's B-squad line-up.
I wasn't too impressed by the press release today.

M$ is taking a big risk with this Kinect thing, and they didn't announce any hardcore games. They are angling for a casual audience but they have a product that will prove to be too expensive and will not be able to compete with the cheap $200 pricetag of the Wii.

Also, the PS3 move looks much more promising-- it has far more precision and a game lineup that seems to appeal equally to both hardcore and casual fans.

Wii is only going to last 5 years or so anyway, like all Nintendo consoles have up to this point. In 1.5 years, the Wii will have finished a normal 5-year life cycle. What will be far more interesting is to see how the Wii's successor can reclaim hype and momentum once Kinect and Move start becoming more popular.