Robert Downey Jr.: Iron Man

Last but certainly not least, we've got Robert Downey Jr. as Iron Man. Because of his history with substance abuse, when Marvel Studios was looking for an actor to play the genius playboy philanthropist, Downey was not at the top of the list. Other actors that were in line to play Tony Stark were Hugh Jackman, Clive Owen, Timothy Olyphant, Nicolas Cage and Tom Cruise, so it came as a surprise when Marvel Studios, which was much smaller at the time, took a chance and chose Downey to be the face of the franchise. What seemed like a huge risk at the time paid off big in the end. The film gave birth to the Marvel Cinematic Universe and revived Downey's career. Downey played Iron Man for over 10 years, appearing in nine MCU films, going on to become one of the highest-paid actors in the world.