Poul Anderson, "Sam Hall"
Isaac Asimov, The End of Eternity
Lois McMaster Bujold, Falling Free
Harlan Ellison, "'Repent, Harlequin!' Said the Ticktockman"
E. M. Forster, "The Machine Stops"
Donald M. Kingsbury, Courtship Rite
Rudyard Kipling, "As Easy as A.B.C."
C.S. Lewis, That Hideous Strength.
Edgar Pangborn, A Mirror for Observers
Robert Silverberg, A Time of Changes
Neal Stephenson, Cryptonomicon
Mark Twain, A Connecticut Yankee in King Arthur's Court
Jack Vance, Emphyrio
T. H. White, The Book of Merlyn
My nominees are the Ellison, the Stevenson and the Vance.
The list of past winners is here. It probably won't shock you that my favorite past winner is ILLUMINATUS! Robert Shea's acceptance speech is here.