Why Monty is not #1 on this list is beyond me. As others have stated, he put method acting on the map and was the first big star to make male sensitivity ok on the big screen. Perhaps many are unfamiliar with his work, but after studying film for years, I still rate The Misfits, Suddenly Last Summer, and A Place in the Sun among the best films ever. Monty could add allure to even mediocre scripts like Lonelyhearts and Raintree County. A tortured soul who couldn't admit his homosexuality, he is the best screen actor of all time.