I like the new movie incarnation a great deal, but he bit the dust (Sorry about that, but he did). That means no new sequels with the new incarnation of the Joker.
Mark Harmill had the best freaking joker laugh EVAR! I agree that we need his name on the vote. He would get the majority, I think.
Heath Ledger, we will miss you, but you died so strangely that I can't help but dislike you. It was either drugs, metal disorder, suicide, or whatever. You gave your best performance as Joker and died. Maybe, just maybe, the persona of the Joker has become too Dark and sinister. The Joker was a gag by the writers who were feeling uncreative at the time. Now he has become a pop icon.