For fiction, I'd probably say Gravity's Rainbow, by Thomas Pynchon. You need a Ph.D. in history, literature and mathematics to understand all of the obscure references buried in its magesterial text, but that's part of what makes it great.
Mine too. I think Coppolla did the movie a disservice not exploring the Luca Brassi character more. He was one of the most interesting people in the book.
In fact, take as a whole it is probably more of a constructed racial myth than just fantasy.
Atlas Shrugged
I'd have to say Zen and the Art of Motorcycle Maintenance by Robert Pirsig. It's 2 books in one -- a philosophical treatise on the nature of materials/substance/quality and a travel memoir of an actual motorcycle trip that the author and his son took on his Honda Superhawk in the 60's.
Honorable mentions: William Gibson's Sprawl Trilogy -- Neuromancer, Count Zero, Mona Lisa Overdrive
Douglas Coupland: Generation X
William Least Heat Moon: Blue Highways
William S. Burroughs: Naked Lunch
Atlas Shrugged
Same here, I'm glad it's finally being made into a movie. I just hope they stay true to the book.