1. Marlon Brando - Don Vito Corleone in The Godfather
Paramount Pictures considered many big names for the head of the Corleone family, but they were very hesitant about casting Brando, as he was now washed up, according to producers across Hollywood. But Francis Ford Coppola was adamant that Brando be cast, and the studio eventually agreed. Boy I bet they are glad about that decision. As difficult as he was to work with, there is no doubting that Marlon Brando put in some marvellous performances throughout his career, and this is the most defining one. This film would have still been great without him, but it was his presence that made it one of the greatest of all time, and helped to set the stage for The Godfather II.