chaos: A tie between FFVI and FFIX. So many great pieces from both games, although the other Final Fantasies had at least one theme that I fell in love with.

Rubedo: Final Fantasy IX for the many songs played as you enter different towns/cities, as well as songs that really portray the mood ("You're not Alone" being my favorite). FFVI had Kefka's Final Boss song as well, so it is really hard to choose.