Margaret Atwood, for literature. I hope that she will win while still around. (Actually, that's redundant, come to think of it, since Nobels only go to living recipients.)
There aren't too many writers who (like her) have excelled as novelist, poet and critic--and who have largely defined their nation's cultural identity for a particular time in history.
(She did win the 2000 Booker Prize, though, for "The Blind Assassin." Not a bad consolation prize, should the Nobel never come through!)