I'm not sure if neither "Kiss Me Goodbye" nor "Symphonic Poem ~ Hope" could be considered the main themes of FFXII. As far as I know, they both play only during (SPOILER)the ending scene and the ending credits. You won't hear them in any other part in the game. If you want to hear what I'd consider the main theme, it's played in several songs in the game, but I don't think it has a stand-alone track. "Opening Movie (Theme of FINAL FANTASY XII)" (part 2:30-3:30), "The Dalmasca Eastersand" and "Theme of FINAL FANTASY XII (Production Announcement Version)" (part 2:05-3:00) all contain the main theme of the game.

This 31-track collection of Final Fantasy XII's music reminds me of FFIX's Uematsu's Best Selection album, which contained 33 songs (32 tracks from the game and an extra one). Not bad, although many great songs from the game are missing from this FFXII album.