The Joker
Whether it's Heath Ledger's version or Jared Leto's version, this is a played out one. Please don't go as Jared Leto's Joker. It is an insult to the franchise and to Heath Ledger. The Heath Ledger portrayal wasn't even a good costume in 2008. It could've been, but every single guy went as that for Halloween that year. Great movie, great portrayal, great costume...but it's played out. It's as common as Dracula or Superman.
[Photo via @joker.lovers]