My first thought is of Shego in Disney's Kim Possible, who actually says in one episode, with emphasis, "I. AM. EVIL. Have I made myself clear?" when trying to disabuse her clueless big brother Hego of any notion that she still is a hero at heart. There is also the Evil Genius of Time Bandits, played by David Warner (who's so very good at being bad, as we all know). Will try to come up with others and get back to you.