Battle Theme FFX
Boss Theme FFVII
Final Boss Theme FF VI ( Dancing Mad )

Town Theme FF II
City/Castle Theme FF IX ( Village of Dali )

Mountain/Volcano Theme FF I ( Mt Gulug )
Forest/Swamp Theme FF VI ( Phantom Forest )
Ocean Theme FF X ( Besaid Theme )
Plains Theme FF IX ( Crossing Those Hills )
Airship Theme FF VIII ( Ride On )
Supernatural/Otherworldy Theme FF V ( Exdeath's Castle )
Final Dungeon Theme FF VIII ( The Castle )

may change answers later on *