People. Peter Weir. He needs to place really high on this list. He was on the last one, but he is so often unsung that even I forgot to rank him.
I think his best movies speak for themselves:
Picnic at Hanging Rock (1975)
The Last Wave (1977)
Gallipoli (1981)
The Year of Living Dangerously (1982)
Witness (1985)
Dead Poets Society (1989)
Fearless (1993)
The Truman Show (1998)
Master and Commander: The Far Side of the World (2003)
This here is a no-brainer.