As far as games go, I personally would get a PlayStation 3 if you're looking to get some great games immediately after purchase, or get the Wii U if you're looking for some ports immediately after purchase. By and large, the PS3 already has a solid library regardless of if you fancy those sorts or not. The Wii U on the flipside is a brand new console even by the time of X-mas, so it won't have a solid library even if you factor in the numerous ports. You'll have, what, around 30 games to choose from for the Wii U whereas you have far above 300 for the PS3. A couple years later and I expect the Wii U to have the same sort of games the PS3 has in addition to the kiddy Nintendo shovelware and the one or two Zelda games, but you're talking about within a month or so of the Wii U's launch. There won't be much to pick and choose from, and as the console hasn't released, we couldn't say as to whether the thing works or not. The PS3, however? Solid Internet, all sorts of multimedia services, great game library that you could tap into immediately since it is pre-existing, etc.
There's also the issue of backwards compatibility. All currently announced Wii U models will be fully backwards compatible with all Wii games, whereas only the very old (launch and a few after) have backwards compatibility with PS2 games. Will you be looking at your new purchase with elder systems in mind? If so, I would aim for the Wii U. If not, well, you know what I'll say in this instance.
But, it isn't only about the games in question. As I said, Internet connection is a thing. I won't comment on either system as the Wii U hasn't even launched (and as far as I know, no comments have been made as to its online multiplayer component), but are you going to buy either system with online gaming in mind? I hear many comments of the PSN being faulty and lacking dedicated servers (which is true, AFAIK). Knowing Nintendo, I expect it to be much the same [and, speaking from a Ninty online gamer's perspective, their systems do experience a ton of lag simply because servers are terrible, in addition to playing with people of varying Internet connection strengths].
The controllers, I don't think you'll have much trouble with on the long term, so I won't comment much. The Wii U GamePad is a behemoth, but you can opt for the
Wii U Pro Controller immediately on launch if you so choose (bear in mind, some games require the GamePad). The PS3 has the PSMove which as far as I know is underused and naught but a rip off the Wiimote. And it also has the DualShock3, a staple for my own repertoire.
And another thing to consider is multimedia. The Wii U, despite being a completely modernized system as far as graphical display goes,
cannot play CDs, DVDs or Blu Rays. You'll have to rely on the free application,
Nintendo TVii, for your multimedia experience on the Wii U. Now, I don't know the full details, but I believe a quick video may be of use:
[video=youtube;08O0G9CjcI8]http://www.youtube.com/watch?v=08O0G9CjcI8[/video]
The PlayStation 3, however, plays
Blu Ray, DVDs and CDs, in addition to having an Internet browser among other things. I'm not everyone, but I personally don't use my system to listen to music (except my PC). However, you may get a kick out of multimedia, in which case I'll point towards the PS3.
All in all,
by the time X-Mas 2012 hits, the PS3 will be a million fold stronger than the Wii U. However, bear in mind the Wii U is still a new console at that time period, meaning it has time to grow and expand whereas the PS3 possibly could die along the road.
I personally would reach out and grab the PS3, as it'd be stronger. But, if you're looking for something to age with, grab the Wii U.
Sources:
Wii U - Nintendo TVii Trailer - YouTube
http://www.gamestop.com/common/images/lbox/240121b1.jpg
http://www.gamestop.com/common/images/lbox/271108b1.jpg