Surprisingly, I tried the first the Kingdom Hearts and didn't care for it. Were there a lot of changes between the first and second? I have the others except Okami. I'll put that on my list.
Kingdom Hearts II has a much better camera angle and it's more enjoyable IMO. However, some feel the story isn't as good and the game is too easy. I prefer the 2nd, but still like both.
As for good

games, I know several, but I'll try to think of ones I know:
Music/Dance
Amplitude (IMO, VERY awesome)
Frequency
Gitaroo Man
RPGs
Kingdom Hearts
Kingdom Hearts II
Shadow Hearts: Covenant
Shin Megami Tenise: Digital Devil Saga
Shin Megami Tenise: Digital Devil Saga 2
Shin Megami Tenise: Nocturne
Shin Megami Tenise: Persona 3 FES
Suikoden V
Tales of the Abyss
Valkyrie Profile 2: Silmeria
Xenosaga series (especially Episodes I and III, but they aren't for everyone due to hour long cutscnes)
Action
Devil May Cry
Devil May Cry 3: Special Edition
God of War
God of War 2
Mega Man X: Collection
Metal Gear Solid 3
Zone of the Enders (I liked it, although the 2nd is better to most)
Zone of the Enders: 2nd Runner
Platform
Ape Escape 2 (not for everyone, but I sure love them)
Ape Escape 3 (not for everyone, but I sure love them)
Jak & Daxter
Jak II
Jak 3
Klonoa 2: Lunatea's Veil (Very fun 2.5D platformer)
Sly Cooper
Sly 2
Fighters
Guilty Gear XX: Accent Core
Tekken 5
Different
ICO
Katamari Damacy
Shadow of the Colossus
You already own R&C and FF I see. There are many, many more I could recommend, it's just that it would take some time and research (I can't remember all the games I use to own, since I had over 200

games at one point).