It's had a great launch, no doubt about it, but I have one nitpick with your approach.
Kinect launched both as a bundle - which I will accept as a new platform purchase - and standalone selling to existing customers - which I struggle with as those have to been seen as peripheral sales.
The last figure from ioi quoted 40% bundles and 60% standalone so for me the correct way to view it is (taking a rounded 4 million figure):
sales as a platform (360/Kinect bundle) - 1,600,000 million
sales as a peripheral (Kinect only) - 2,400,000 million
I just don't think you can fairly count sales that only happened because there was an existing install base against Wii or any other console at launch with zero install base.
Try to be reasonable... its easier than you think...
