Putting aside PC (since, the question *is* about those 3 systems). And its not like the PC's existence is new. Its always been an alternative to the consoles.
I'm probably going with Wii U.
If its like the last generation, most of the Xbox games I feel like getting will be able to be played on the PC and I already have a 360 controller. And there weren't many PS3 games that really caught my eye. So the Wii will probably that system again that has games that I want and aren't already on a superior system.
All of this DRM stuff has ruled out the Xbox for me and I still don't trust the PS4. So the Wii U wins in that regard.
Plus, I'm a pretty big fan of platformers. And by far, the Wii U will have more of those. Though I am curious about how Knack will turn out and if Sony wants to make more platformers.
And oh yeah, Sonic: Lost World. Which has sold the Wii U more for me than Mario 3D World or Nintendoland ever has. Not just because I'm a Sonic fan, but because for once it looks like Sega is putting extra effort into their game while Nintendo keeps trying to play things safe (Nintendoland = bunch of mini-games with Mario's face on it, Mario 3D World = Mario 3D Land with multiplayer and a catsuit...this is seriously intended to be the successor to Mario Galaxy??).
Not that my opinion holds too much weight, its far too early before I even think of getting a new system considering pricing, early launch system glitches and limited game libraries.