Dear Lazyweb: Reading Recommendation

I'm looking for a book to read but along a certain line of reading. Think Robert Heinlein's Starship Troopers or Ayn Rand's Atlus Shrugged. Books that strongly expose a philosophy through narrative. I don't particularly care what philosophy, but I enjoy reading these sorts of things in this fashion. Any suggestions?

[Edit: as this is part of an archive now, I figured I'd note down some of the better comments that come in on livejournal, where the above was originally posted.]

American Gods -- Neil Gaiman (done)
The Unbearable Light of Being -- Milan Kundera
Island -- Aldous Huxley
Forever War -- Joe Haldeman (done)
Old Mans' War -- John Scalzi
The Door into Summer -- Robert Heinlein
The Dispossessed -- Ursula Le Guin
The Lathe of Heaven -- Ursula Le Guin
Zen and the Art of Motorcycle Maintenance -- Robert Pirsig
Siddhartha, and Steppenwolf -- Hermann Hesse
Jonathan Livingston Seagull -- Richard Bach
Illusions -- Richard Bach
Hyperion -- Dan Simmons (done)
Riverworld, World of Tiers or Dayworld -- Philip Jose Farmer
Fear and Loathing in Las Vegas, The Rum Diary -- Hunter S. Thompson
Ender's Game -- Orson Scott Card (read)
Foundation series, Robots series -- Asimov (read)
Tales of Pirx the Pilot -- Stanislaw Lem
VALIS -- Philip K. Dick
The Player Of Games, and Look To Windward -- Iain M. Banks
The Best that Money Can't Buy -- Jacque Fresco
Childhood's End -- Arthur C. Clarke
Flowers for Algernon -- Daniel Keyes
Out of the Silent Planet, Perelandra, and That Hideous Strength -- C.S. Lewis
Perelandra -- C.S. Lewis
Languages of Pao -- Vance
The Humanoids -- Williamson
Fictions -- Borges
Against the Grain -- J-K Huysman
Mars trilogy -- Kim Stanley Robinson (done)
Anathem -- Neil Stephenson
Lila: an inquiry into morals -- Robert Pirsig
The Canticle of Leibowitz