I voted for the 360, but that is at best an educated guess, and at worst a stab in the dark. Either way, luck will be the deciding factor on whether I'm right or not.
For myself, I don't understand how anyone could choose a PS3 over the 360. I understand the PS3 may have more exclusives, but for the most part anything you can find on the PS3 you can find on the 360, and the difference in graphics won't be worth $200. So for sheer dollar value alone the 360 seems to be the obvious choice for me.
The Wii is just too much of a wildcard to really say anything for sure. It might catch on, but I think Mai was right when she said it was an "and" system, as in, people will buy a PS3 or a 360 and maybe a Wii. The problem is I don't think there will be too many gamers that settle for the Wii only. The tried and true control setup for videogames will, in my estimation, endure one more generation at least. Even if the Wii is "revolutionary," I don't think it will really catch on this gen.
While I have worked out which consoles I am willing to buy with logic, I understand fully that said logic plays but a small role in a gamer's decision to advocate one console over another. So while I would expect my reasoning to reign supreme I also fully expect to be surprised. If that makes any sense...