Finally Beat FFVII Crisis Core and I was wondering if there was any other good RPGs on the system.

kingdom hearts birth by sleep

So many. The PSP is an RPG beast:

• Persona 1, 2, and 3
• Valkyria Chronicles 2 and 3
• Jeanne d'Arc
• Final Fantasy Tactics
• Final Fantasy 1
• Final Fantasy 4: The Complete Saga Collection
• A whole bunch of Ys games
• I'm not sure if it's an RPG but Valkyrie Profile
• Downloadable PS1 versions of FF1, 2, 5, 6, 7, 8, 9, Chrono Cross and Chrono Trigger
• A Kingdom Hearts game that probably has a dumb subtitle
• I think Tactics Ogre is an RPG but I'm not sure

I know I'm forgetting some.

I recommend all the NIS games, such as Disgaea, Disgaea 2, Phantom Brave, and ZHP. All of these games will suck you into hours of great game play. I have spent about 200 hours in each of them.

@mosespippy said:

So many. The PSP is an RPG beast:

• Persona 1, 2, and 3
• Valkyria Chronicles 2 and 3
• Jeanne d'Arc
• Final Fantasy Tactics
• Final Fantasy 1
• Final Fantasy 4: The Complete Saga Collection
• A whole bunch of Ys games
• I'm not sure if it's an RPG but Valkyrie Profile
• Downloadable PS1 versions of FF1, 2, 5, 6, 7, 8, 9, Chrono Cross and Chrono Trigger
• A Kingdom Hearts game that probably has a dumb subtitle
• I think Tactics Ogre is an RPG but I'm not sure

I know I'm forgetting some.

I know what you're forgetting: 75% of the PSP library.

Ys Seven! More of an action-adventure oriented rpg, but an rpg nonetheless. It is quite good.

Get Tactics Ogre if you're into strategy RPG's.

Or just get it if you're into games with amazing stories that you can actually have a tangible impact on.

Man, pretty much everything I wanted to suggest has already been said. However, I will also give my vote for Kingdom Hearts: BBS, even if you aren't into the universe/story etc it has some of the best (my personal favorite anyway) combat in an action rpg out there, infinite melee combos goooo. 

Tales of Eternia.

Final Fantasy Tactics: The War of the Lions has to be my favorite RPG on PSP. I love building an army of Heavy Armor Monks.

one word. Lunar

one word. Lunar