Those Chosen by the Planet really should get more love. It's so simple yet effective, and used in brilliant ways as well. It kinda has two layers, so when you're talking with Sephiroth before he goes full evil it's very understated, just a heartbeat on the drum and some chimes, then he storms out to find JENOVA and tear up Nibelheim and it kicks into the full theme, and it's damn scary.
Actually... yes. It's wonderful. ALSO wonderful from the vocal albums and underappreciated in general is Relm's Theme:he best Prelude is in no Final Fantasy, it is this one: https://www.youtube.com/watch?v=4reZp854LZg