6) James Franco
Similar to how Ledger almost played Batman and instead went on to play the Joker, James Franco was one of Sam Raimi’s final choices to play Peter Parker, though he of course lost out to Tobey Maguire in the end. Raimi clearly liked the guy, though, and instead cast him in the movie as Harry Osborn (the pair later also worked together on 2013’s Oz: The Great and Powerful).
While Franco has gone somewhat off the boil (and off his rocker) recently, he did actually give a pretty strong performance as Harry Osborn, so we think Raimi called it right on that one. The actor clearly works best when there is a bit of sleaze to his character, so him playing the complete good guy Peter Parker probably wouldn’t have worked out anyways.