I will say this necro is entertaining. People predicting 3-4m were "ballsy" this thing is already at around 10m less than a year after launch. I think it will crawl form here to around 12-13 mil.
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