4. Heath Ledger - The Dark Knight
One of the ultimate examples of an actor completely confounding expectation and proving his detractors wrong, Heath Ledger's mesmerising performance as The Joker not only earned him worldwide adoration from the comic book community, but garnered him a posthumous Academy Award for Best Supporting Actor, and played a part in elevating the comic book film to new heights. When he was cast, however, it was a different story; Ledger was enjoying critical acclaim for his work on Ang Lee's Brokeback Mountain, and Batman fans simply thought that "the guy from 10 Things I Hate About You" didn't have the gravitas to make such a showy, edgy role his own. And to be fair, it didn't seem to click for a while, at least until that first trailer dropped, and we knew we were onto a winner. By the time the final film hit our screens, Ledger had completely proved his critics wrong, delivering an indelible, unforgettably menacing performance that stands among the best in the history of the Hollywood blockbuster. But boy, did he have to face a trial-by-geek or what?