I am thinking about expanding my PS2 library a little bit and I was wondering what you guys think are the best and what I should get.

I like JRPGs mainly and already got FFX, FFXII, DQVIII, Star Ocean. I know that their has got to a be A LOT more games that I am missing out on. Feel free to suggest anything from other genres though.

Dark Cloud 2.

Persona 3 FES
Persona 4
Jak and Daxter (all three)
Rumble Racing (kick ass Mario Kart style game)
SSX Tricky
Gran Turismo 3/4

Rogue Galaxy

ICO
SotC
Okami
Burnout 3: Takedown
Burnout (still love the first one, racing in a city bus, can't go wrong with any ps2 Burnout)
J&D: Precursor legacy
R&C: all of them
Silent Hill 2
Colin McRae Rally 3
GTA: San Andreas
Baldur's gate Dark alliance 1 & 2
Champions of Norrath
SSX 3
Need for speed: Hot pursuit 2
We love Katamari
Herdy Gerdy
Indigo prophecy / Fahrenheit
MGS3

Suikoden 5. Slow start but great game.

THese are my favorite JRPG's. on it.

1. FFX-2 (:D :D :D)
2. Persona 3: FES
3. Shadow Hearts: Covenant
4. Persona 4
5. Valkyrie Profile: Slimeria
6. FFX

Shadow of the Colossus.

Kingdom Hearts II, God of war II, Ratchet and Clank, Shadow of the Colossus, FFX............

I could list off so many games like KH 1, CoM, 2, SOTC, R&C, J&D, Sly, FF X, GoW 1, 2, but all of them have HD collections on the PS3 lol.  One hidden gem that I loved that no one will probably recommend is Metal Arma A Glitch In The System, idk how hard it is to find, but it you can I'd say pick it up.  Well first look it up and see if you like it.