jenova theme(VII), lagunas theme(VIII), you are not alone(IX), four fiends(IV), battle on the big bridge(V), seymour final battle (X)
Yeah FF series is up there alright, the music always fits the games, though other games with other settings do a finer job in some areas, star ocean 3's battle with crossel is an amazing fighting tune, and TES: Oblivion has some of the most excellent orchestrated tracks for world exploration.
All boils down to taste though, my favourite VG music for example is from sonic 3 & knuckles. doesnt mean I dont like others.
PSN:TheDragonzord >_> Sonic The Hedgehog 3 & Knuckles HD remix please