I'll break the barriers so quickly and not say someone from 7.
Kuja, from IX. Why?
Without going into too many details and spoils, he brought so many new things to my perceptions of a villain. Aside from his feminine appearance which people still can't get over apparently, He's much more of a suave manipulator than most of the villains and does in an (Amazing!!) poetic and narcissistic manner that just makes you want to punch him in his *pretty* little face. He's also a complete A-hole while he's being so polite and constantly mocks the heroes. He's got a huge sense of pride, and again, he's self-centered so much to the point of his final goal in the game:
click to show spoiler
To destroy all existence simply because he himself is going to die. I personally ADORE Trance Kuja in almost every sense of the word short of any form of affection.
Also, his themes are amazing. I listen to 'The Dark Messenger' like every day.