Well, every FF villain (except Kuja) sucks compared to Kefka. And Garland was pretty badass in both FF1 and FF9. He was Kuja's master in FF9, and he was Chaos in FF1. That's fairly impressive, either way.
Magic Emperor Ghaleon's still one of the best RPG villains ever. The guy just screamed menace, but you sort of understood his actions at the same time.