I personally think the Wii U is shaping up to be a justified purchase already, though I suppose you'd also have to have a wide taste in games. I've bought about 8-9 Wii U games in a year. And I rarely BUY that many games in a year, period. Nintendo just needs to step up their online game, really, among a few other refinements to the firmware.
I have faith the PS4 will be the same situation in terms of games. There is nothing interesting right now, but I'll give it a year (well, technically I don't need to, as my brother is getting the system at launch, but there won't be any interesting games to me for a while yet).
As for the Xbox One, Project Spark is the only thing that interests me (I would say DR3, but that would literally be for no reason other than the Mega Man X armour!

). The thing is, I don't have faith in Microsoft regarding exclusives, and their equivalent to PS Plus is a joke. And it's a less powerful system. And more expensive (because everyone loves Kinect). So no matter what angle I look at it from, I can't find reason to take interest.
Plus, I still am not confident those reversals they made regarding those stupid policies they had in mind at first, are permanent.