As a guideline you (typically) see somewhere between 2 and 4 times the average weekly/monthly sales for a system in November and December. I personally expect the PS3 and XBox 360 to sell between 750,000 and 1.5 Million units per month whereas the Wii will sell between 2.5 and 4 Million units per month.
The one thing I think that could end up being interesting this christmas is that (currently) there has been a drop in consumer confidence which (if extended through the holiday season) could mean that people spend less and stay away from larger purchases.







