If you like beat-em-ups, both X-Men Legends and Marvel Ultimate Alliance are worth a run-through on the PSP. Lenneth is a great pick. Most of the stuff I play for my PSP tends to not be RPGs, though. Both Metal Gear Ac!d games are great, and cheap, now.
I'm more interested in MGS Portable Ops, as I *loved* MGS3.
Is XMen Legends anything like Age of Apocaplypse? I played that on PS2 and enjoyed it.
I don't know Gurumin - but I'll look into it, thanks.
I haven't forgotten about Crisis Core, but that's ages away yet.