One theme that I believe hasn't been mentioned yet is The Decisive Battle from FFV. If I'm remembering correctly it plays in the first phase of the final battle before being replaced by a different theme which is still good but not quite as memorable. I like it a lot, but I'll echo others in this thread and call Dancing Mad my favorite, followed by Dark Messenger. I also agree that One Winged Angel gets a little bit too much credit despite being a really strong piece.