Final Fantasy VII
Quite famous and definitely the cause of my love for silver haired men, Sephiroth was the main villain in FFVII, who tried to bring Meteor down and destroy the Earth. Cloud stopped him--though with him coming back in Advent Children in appears that Cloud didn't actually finish him off(wee!!). Before Sephiroth became evil, he was the greatest hero that had ever lived- the Great General from SOLDIER.
(I'm Sarak, btw-- FF7 fanatic)