In your opinion, who do you think should be the next Joker?

I personally think that Heath Ledger did an AMAZING job!! It is unfortunate that he is gone. He was a really talented actor, and I think that he wasn't able to prove that soon enough. For those of you who have seen The Dark Knight, you know that it was left open for another movie to follow. And obviously, the Joker will play some part in it. Who do you think has what it takes to take up where Heath left off?? It will DEFINITELY be an extremely difficult act to follow!