To be honest I think this time is a good time to get a PS3, if you never did. PS Plus especially right now is better than ever. (make sure you subscribe to it so you get to play Vanquish, inFamous 2 and LBP2 for free!)
That and there are promising exclusives around this time. Ni No Kuni and PS All Stars just came out and they are both very solid, and there's still Puppeteer, Sly 4, Last of Us and MLB 13: The Show around the corner. You also get the great range of exclusives you missed (Uncharted, inFamous, Demon's Souls, WipEout to name some...), and great HD collections of previous PS2 games if you never played them. (I recommend MGS and Jak, personally. :P ) The only thing it has going against it right now is that it's usually the worst for multiplat titles, but I don't think that matters much now and the price is great.
Wii U can wait. As much as I love NSMB Wii U (most fun I've had with a 2D Mario since I can remember <3) and Nintendo Land, there's literally nothing special about it. I'd wait until more games come out for it.
Off to play Gravity Rush...
EDIT: Missed you post about the 360. Well it depends on your preferences, and I'd take a look at both's selections of games before I decide. I've only bought the PS3 recently, but I personally like it better than the 360. But again, it's preferences.