Yasunori Mitsuda was my first favorite. Chrono Trigger is a pretty exceptional debut soundtrack for him, and he surpassed it with Chrono Cross, and Xenogears, both of which are as close to perfect as I've found in game music.
Then Masashi Hamauzu came along, and I think he has surpassed every other composer related with SquareEnix. Actually, it's because of him that I got into classical music, since I already liked Hamauzu, and read that he was influenced by the likes of Debussy. That classical background explains why he's been so good at arranging pieces for those piano albums. He also sang in the choir for One Winged Angel, apparently.