Its hard to say, part of the reason the PS2 can still be kinda relavent now is because when it was release it was state of the art tech, the Wii was dated from the day one. I think the 360 will be the cheap parent choice from here on out. Nintendo can try and milk the Wii all they want but you will not see new Wiis being sold with 18 months of the WiiU being released. Nintendo needs to release that they will live or die by the WiiU, I like the fact they are making the tech in the WiiU far superior to the current gen, while it will not be state of the art it will be an upgrade from the PS3 and 360 in the graphics department. This will give Nintendo a change to go after a market they have not had a shot at since about 1996... the early adopter techies that have to have the best thing avialable. The WiiU's 1st year it will have the best looking COD, Madden, etc this will hopefully give the WiiU a foothold.
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
