I'm borrowing my brother's Vita long-term (in return for the hundreds of hours he's racked up playing DayZ on my PC), so I've been playing Uncharted: Whatever (too dull for my liking, also very annoying with all the tutorial screens, can't be bothered with it), Wipeout 2048 (excellent fun), GT PSP (also excellent) and Super Crate Box which has to be the most addictive game I've played and well worth the £2.50 I spent on it. I think I've played that one more than anything.
I've also tried remote play with my PS3, Pixeljunk Shooter is far more fun than I remember... MGS:VR Missions is too tricky without shoulder buttons though. I bought Metal Gear: Portable Ops earlier but I haven't picked the Vita up since then. I had to delete a game to install it - I picked GT PSP as it was the smallest at 1010MB - and now I have 1036MB left on the 4GB card... GT PSP only needs 1046MB to install but I just don't have that 10MB to spare, unfortunately. I'm toying with the idea of picking up an 8GB card but I've already spent something like £20 on games for a console that I don't actually own!
I've also been slowly carrying on with Real Racing 3 for some reason. I honestly don't know why I bother though since the game lets you win easily if you have all the non-gold upgrades on the best car up until the last three tiers, then you can only win once you buy the gold upgrades. Predictable and greedy.