PS3 and 360 will have almost complete and identical game libraries, where as the Wii will have it's Nintendo exclusives and the occasional similar sports title, but thanks to the Wii's unique control scheme even if the other consoles do have a title or two thats on the Wii, the gaming experience and control will be better on Wii.
So thanks to the nearly identical hardware power of PS3 and 360 all the fancy high def drivers, shooters, sports and RPG's will most definetly be on both systems with almost no exclusives left to single out one over the other.
While the Wii will have our favorites like Super Smash Brothers Brawl, Super Mario Galaxy, Metroid Prime-3, Zelda, Starfox and many more especially via Virtual Console. Now the graphical whores out there will tell you " Yeah well the Wii won't have the same titles because the hardware is to obsolete to run them "...but anyone that has seen Resident Evil 4 or a gameplay trailer of Metroid-3 won't be too worried about the graphic potential of the Wii besides we'll always have the most fun, in depth game system on the market.
Just check world wide sales, and install base on any news channel or website if anyone doubts it.