John Cazale
One of the greatest actors of the 1970s. He was in a total of five movies before he died of skin cancer in 1978. These movies were The Godfather, The Godfather Part II, The Conversation, Dog Day Afternoon, and The Deer Hunter, all of which were nominated for the academy award for best picture, three of which won.
It's a shame that John Cazale's skin killed him at such a young age, because if he kept going, he would have eventually be easly recognized as one of the greatest actors to come out of Hollywood in the last sixty years.