New XBox Controller: As Add-On Only

Microsoft’s no-controller 3D motion and voice recognition technology (presently known as “Project Natal”) is being designed for the existing Xbox 360, not an imaginary “performance-upgraded” one.

At least that comes from an official statement released by a Microsoft spokesperson:

As the Xbox team stated at E3 two weeks ago, we are not even halfway through the current console generation lifecycle and believe Xbox 360 will be the entertainment center in the home for long into the next decade. Project Natal will be an important part of this platform, but we have not confirmed a launch date at this time.