Keep in mind if you get the vita or ps3 you can get PSN+ and get some of those game for free.
I got free (for vita) Virtue's Last Reward, Star Wars Pinball, Uncharted Golden Arbys, etc
This is what I was going to suggest. For the price of a game, you can buy a year of PSN+, which is totally worth it thanks to the good free games.
And if I were choosing between the three, I'd actually go with the PS3. Lots of great games, including several of the PSN+ free ones, and you get a BluRay player.
If that's out, then it's a tough call, but I'd probably go with Vita for the free games. I've got both Vita and 3DS, and I've purchased about the same number of games for both.