Wii almost certainly.
1. It will be the second console of choice for those families with 2 consoles. (okay, in some families the first console of choice and a PS3 or X360 as the runner up)
2. Even as HD TVs become more affordable, there will be a sizable amount of the world's population that can afford an inexpensive console and run it on a non-HD TV. Wii will be that console all the way down to the $99 version.
3. Nintendogs was the game that really brought in the females to the DS Lite. And Brain Age for the more older adults. While Wii Sports has done the same for casuals/families, I think that the Wii game(s), that pulls in the females and older crowd with the same impact as those DS games, have not been created yet. When we see the 1M pink Wii and the 1M dark mahogany Wii sell, we will know what those games are. (Right now, I can't imagine PS3 or X360s selling in those colors!) Wii Fit might be one of those games, but for a market that we will say in two years... "Oh, of course, I knew it would bring in THOSE people."
PS3 might do 100M, but not for games. If it was strictly game dependant to hit 100M, I'd say no way. But it has Blue Ray. And if BR becomes the standard soon enough, it could sell enough for non-gaming uses, which combined with the sales as a gaming machine might put it over the top. The two problems it has in getting there is how much is Sony willing to keep losing on the console to keep strong sales up, ie, the $299 scenerio in xmas 2008. And how much is Microsoft willing to lose to keep the X360 at a better price?
Ironically, I could see if BR is crown king, that the PS3 is hurt by that. The arguement that PS3 is needed to make sure that BR becomes a standard is over. And the investors will want Sony to stop dropping $$ into the PS3, so they can enjoy the BR profits.
Torturing the numbers. Hear them scream.
