1. Kevin Costner (Robin Hood: Prince Of Thieves)
Hot off the success of his Oscar winning 1990 feature Dances with Wolves, Kevin Costner decided to bring the iconic character of Robin Hood back to the big screen in 1991's Robin Hood: Prince of Thieves. Costner seemed like a natural fit for the dashing hero and Dances with Wolves dominant performance at the Academy Awards made him seem infallible at the time. While Princes of Thieves won audiences over, critics took umbrage with Costner's performance, particularly his unwillingness to even attempt to give one of England's most famous heroes an English accent. Despite all expectations, it seemed that Costner had been miscast and his inability to bring goods cost the film its credibility. Prince of Thieves might not have been quite as large a box office draw without Costner's name attached to the project but a different actor may have been able to do the character justice and bring the role some much needed credibility. There you have it, our list of 10 terrible casting decisions that ruined an entire movie. Will Ben Affleck's upcoming role as the Dark Knight earn a spot on our list in the near future? Let us know what you think in the comments.