X360 sales in the USA are largely on the $75 giftcard for the $300 sku at Walmart.
Next week has no such deal (Dec 25 week), just a $20 discount on the Kinect bundle at Target but its the biggest shopping week of the year in the USA, and so the fall off won't be too bad.
Wii / PS3 have deep discounts for Dec 19 in the USA (Sunday before Christmas). After that, Wii has $50 discounts at Toys R Us and Best Buy.
With another 900k - 1m week in the USA for Dec 25, the Wii should be well on its way to a second 3.5m ish December in the USA.
People are difficult to govern because they have too much knowledge.
When there are more laws, there are more criminals.
- Lao Tzu