Director Christopher Nolan says that he won't bring back The Joker in Batman 3 or in any installment of the franchise while he's in charge.  From the latest issue of Empire Magazine [via Obsessed with Film, emphasis theirs]:

“No”, says Nolan emphatically and unhesitatingly. He resists elaborating simply because, quite understandably, he says, “I just don’t feel comfortable talking about it”.

It's good to know that Nolan is choosing not to make the crassest decision of all-time.  Besides, who could you recast?  Heath Ledger's Joker is a singular performance, and while it can be impersonated (tip: always act like you're really thirsty), it can never be replicated.  So let us simply resume speculation over who will be the villain of the next Batman movie. Batman 3 (tentative title) is slated to hit theaters on July 20, 2012.