6. Zooey Deschanel
Zooey Deschanel is the epitome of "adorkable," and Harley, despite being crazy, oddly enough is kind of adorable. With those big blue eyes that pop out at you and her quirky sense of humour, Deschanel definitely has it in her to play someone who's a mix of cute and crazy. If the filmmakers were to interpret Harley similar to that of the animated series, Deschanel would be perfect. And if they were aiming to go for a much darker version of this character, it'd be great to see Deschanel reveal darker depths as an actress. Deschanel is also such a likable and appealing actress that she'd be able to make Harley pretty likable and lend her an air of sympathy. I could even see her stealing scenes from the J man himself.