The answer is obvious, although no-one has said it out loud yet. It will of course be: Nintendo!
With Microsoft and Sony battling it out to win over the video game fanatics, charging ridiculous high prices for the casual gamer (400-500$ pricepoints will not convince anyone to buy these consoles who is not a hardcore gamer). Nintendo will slash their prices as much as possible for the holiday season and suddenly the Wii U will be the best selling console ever.
The Wii did it before, even though it was the worst hardware, had no interesting games besides Nintendo's own franchises but ulitmately appealed to everyone who is not playing Halo or Call of Duty.
To me it doesn't matter, as usual I will buy all three of them (obviously the lifecycle of video game consoles now reaches 7-8 years so the investment in 3 of them is quite acceptable) and just decide based on the games I want to play which one to use.