Anybody else out there into importing their games?

At the moment, I've been concentrating on portable gaming systems since they don't have as many restrictions as the consoles do (without mod chips, that is).

I've got about all the must-have DS imports at the moment (I'm rather addicted to Osu! Tatakae! Ouenden). Any must-have PSP titles that I should pick up? Space Invaders Galaxy Beat looks like quite an interesting take on the classic game that I might want to get -- I'm a big fan of Rez, so this seems like it might be on a similar concept in a way. Preferably want games that doesn't have too much of a language barrier (not *that* good at Japanese yet) and probably won't see the US or the Japanese counterpart is much better.