Pretty much after Star Wars, Hamill's career as an actor was sorta over. (See The Guyver if you don't believe me). However, a new , more awesome and sinister Mark Hamill was forged. Especially when he landed the voice of The Joker in Batman: The Animated Series. Jeff Bennett and Kevin Michael Richardson also put themselves in the shoes of the Clown Prince, but no one can land the role like Hamill.
Hamill played Fire Lord Ozai along with Grey DeLisle in Avatar: The Last Airbender (2005).