We could have two Joker's of this generation, and I don't think a lot of people would mind if the actor is incredibly talented, but if the Joker doesn't appear, I won't complain. I've got two great performances to watch between Jack Nicholson & Heath Ledger.
And one last thing I'd like to add; I'd love to be the Joker of the next generation if I'm as good an actor as I want to be.