So with Sony's Vita announcement getting me really excited I thought it was time to pick up a PSP and play some of the games I never got a chance to, so far I've picked up

Dissidia Final Fantasy
Persona 3 Portable

And thanks to the welcome back programme
LittleBigPlanet
Modnation Racers
Pursuit Force
Killzone Liberation

So what other games have I missed out on that are worth buying, so far I'm thinking of Final Fantasy 7 Crisis Core and I was considering Peace Walker but I'll just get the PS3 remaster. Take a look at my games collection for some ideas of what I like

I think you have enough for now =p

Half-Minute Hero
Twisted Metal Head-On
Ys

True but four of those are only there because they're free, hard to resist that

CRIMSON GEM SAGA!!!(this game is severely underrated)
Star Ocean: The First Departure
Star Ocean: The Second Departure
Final Fantays VII: Crisis Core
Kingdom Hearts: Birth by Sleep
Tales of the World Radiant Mythology
Persona
Final Fantsy Disidia Duodecim(come with the original dissidia and a new game)
...as you can tell I'm an RPG fan

I'll second the comment on Half-Minute Heroes. It's a quirky little game that's surprisingly fun! I'd also look into the Legend of Heroes games- they're also relatively cheap anymore. Ys and Persona are also good, but those are a little more specialized...

Then I recommend SOCOM: U.S. Navy SEALs Fireteam Bravo because the PSP commercial says it's the best PSP game under 10 bucks which is really cheap for a game, so it's like getting it free....

Monsters (probably) Stole my princess, is awesome and cheap psp mini.

Valkyria Chronicles 2

All the FF games you can get

the god of war games if you cant wait for thier release on ps3

MGS - peace walker

oh and the patapon games. Damn i miss those patapons *goes to buy a psp maybe*

Kingdom Hearts Birth by Sleeppppp!!!!!!