It is an interesting question.
If we look at previous decembers we see
2006 = PS3 - 490k. 360 = 1.1m. = 360 sold 610k more.
2007 = PS3 - 790k. 360 = 1.26m. = 360 sold 470k more.
2008 = PS3 - 726k. 360 = 1.44m. = 360 sold 710k more.
So based on previous holidays 360 has sold more then PS3 quite comfortably.
This holiday is different in that PS3 has a price cut and a new model, so obviously sales will be better.
However what i think a lot of people are missing is that majority of the PS3s sales for November 2009 came from black friday deals. Even with those huge sales PS3 still sold 25k a week less then the 360.
The way i see it i think it will be a close call. History shows that december sales are roughly around a 40% increase from november. If this trend runs true into this december then that would at an estimate put PS3 sales around 994k. Just under a million. If we do the same with 360 would put it at around 1.1m. So again i think we could be looking at a difference that is a 100k or maybe even less.
So based on past trends and factors when you take away the black friday effect i would take a guess that 360 will beat PS3 in NPD sales.
