Persona 4 vs Tactics Ogre PSP - I'm not really particularly impressed with the TO soundtrack. P4 has a really unique feel to it, and it really sets the mood of the game. Admittedly some tracks can get grating in the longer dungeons, though this is a common issue with both games.
Chrono Trigger vs Radiant Historia - Close match, giving it to the one with more than 12 tracks.
Megaman 2 vs Castlevania 2 - Vampire Killer vs. Okkusenman, you say?