I do, had the 360 just had an average Cmas, I think MS would have started to get the gears in motion for the new console in 2 years minimum.
I think this Cmas has added AT least 1 year to the life of the 360. Now think about that, and remember that when someone says "why worry about sales, just play the games"
I think the 360 will have a full 6 year life cycle at the least before the next console is released.
End of 2009 Predictions (Set, January 1st 2009)
Wii- 72 million 3rd Year Peak, better slate of releases
360- 37 million Should trend down slightly after 3rd year peak
PS3- 29 million Sales should pick up next year, 3rd year peak and price cut