I think the Wii U might win because of good third-party support. They're really trying to do something more edgy to bring in the more hardcore gamers while still keeping the casual crowd, which is a good marketing strategy, but it will only work until the NextBox and PlayStation Orbis (that's one of the concept names for the PS4) come out. We should be seeing new consoles in 2014, so the Wii U will have a one and a half year head start. After all, the Sega Dreamcast did, but look where THAT ended up. Hopefully, Nintendo should get some third party support that will keep the console selling until maybe 2016, and that's being generous, considering the Wii has so far lasted until now.
Though, hopefully, they pack the Wii U with the remote, touch-pad AND one controller all packaged for about $300. Also, they need to have backwards compatibility with Wii and Gamecube games if they want to keep their place in the market. If I buy a Wii U, I expect to be able to play Muramasa: The Demon Blade on it, considering that the controller it's coming with will make playing it a dream come true. Also, Bayonetta 2.
They really, REALLY need to step up their game if they want to succeed, and I sincerely hope they got rid of the friend code system and instead follow Sony and Microsoft's examples.