I was just about to add Azula to my list. Everything about her fits her character. Twisted, intelligent, a prodigy, calm in any situation... I think almost every fight scene in the series that included her was great, especially the last 2 with Zuko (in The Southern Raiders and Into The Inferno).Thaius said:Movies: Darth Vader (Star Wars... duh)
Video Games: Tie between Sephiroth and Kefka (Final Fantasy VII and VI, respectively)
Books: Darken Rahl (The Sword of Truth series)
TV Show: Azula (Avatar: The Last Airbender)
Anime: Light Yagami (Death Note)
(Link to awesome Zuko-Azula tribute http://www.youtube.com/watch?v=t2NV6FRCP9s)