5. Orson Welles - Mr. Kurtz
There's no doubting the fact that, had he somehow got his long-scheduled Heart of Darkness adaptation into production, Orson Welles would have had another masterpiece sitting pretty admist his already impressive filmography. Though Darkness, one of Welles' passion projects, never went further than the script stages, and casting decisions were never banded around, it seems plausible to suggest that the Citizen Kane director could well have ended up as Kurtz. Yes, Welles seems perfectly suited to that of the ivory trader who goes insane in the African Congo (a role later immortalised by Marlon Brando in Francis Ford Coppola's modern "remake," Apocalypse Now). Welles, like Brando, would have certainly brought this gruelling, conflicted and debauch character to life - or what life was left of him. Marlow needs to find somebody of great weight and the power at the end of his journey, after all; only Welles would have sufficed.