Seconded: the Ender saga...and read ALL of them. Well worth it! Also, by Orson Scott Card, try Pas****ch: The Redemption of Christopher Columbus. AWESOME.
Also seconded: Asimov, Clarke, Bradbury and Heinlein (my personal all time favorite...read his books: Starship Troopers, The Moon is a Harsh Mistress, *Podkayne of Mars, or Stranger in a Strange Land...and if you like his style enough, find a copy of Time Enough for Love).
Philip K. Dick (Do Androids Dream of Electric Sheep?)
Tom Holt (humorous scifi, along the same lines as Hitchhiker's Guide to the Galaxy...get either Blonde Bombshell or Life, Liberty, and the Pursuit of Sausages)
Poul Anderson (try Tau Zero)
Ayn Rand (Anthem, specifically...yet even Atlas Shrugged has a bit of a sci-fi aspect to it)
Edgar Rice Burroughs' Martian Tales Trilogy
Michael Crichton...anything, really...Timeline is good sci-fi
And that's all I've got for now. Let me know if you try any of this stuff out and like it.*
Snow Crash by Stephenson is really good.
Anything by Zelazny is worthwhile, but the Nine Princes In Amber series is best.
Oh, Octavia Butler's Bloodchild and Other Stories is a personal favorite of mine.
Dune is a must IMO
H.G. Wells - The Time Machine is a great read as well
Gateway by Frederik Pohl
Although not exactly sci-fi, read Neil Gaiman's Neverwhere and American Gods. Both are fantastic and funny journeys into altered reality.
Didn't Neil Gaiman do The Looking Glass Wars??
Edit: Sorry...Frank Beddor
Then I thought, "Didn't Neil Gaiman do The Half-Made World?" and then I was wrong again. Felix Gilman did that one.
Both are good reads, anyway.
Originally Posted by gescom
These are great selections and important to read early on, ten years later though other writers in the genre may give you a bigger hard on for re readability. If you can keep a frame of reference of when these books were written vs the technology when you read them it will blow your mind to think about how they influenced the products that we now have. Seriously if you read Enders Game and think about how they were writing about tablets back in 1985 and now in 2011 we have the ipad and you don't even have to imagine it, it's pretty awesome.
There are some great suggestions here. For any Sci Fi reader there are some must reads some have already been mentioned:
Isaac Asimov - Foundation and Robot Series
Frank Herbert - Dune and Children of Dune Series
J. R. R. Tolkien - The Hobbit and One Ring Trilogy
Roger Zelazny - Amber Series
Robert Silverberg - Majipor Series
Anything from the following authors:
H. G. Wells
Arthur C. Clarke
Some of my personal favorites include:
Douglas Adams - Hitchhikers Series
Piers Anthony - Xanth Series (based on puns) and Bios of a Space Tyrant Series
Terry Brooks - Start with Sword of Shannara Series and then try to read the rest of his works in chronological order. Most all of his series are related to his first Shannara novel by virtue of it being the same world. He had another series called the Landover series witch was unrelated to the Shannara Series.
Jim Butcher - Codex Alera Series
Stephen R. Donaldson - Thomas Covenant Series. Make sure you have a dictionary and thesaurus handy.
Dave Duncan - Man of His Word Series
David Eddings - the Mallorean Series
Reaymond E. Feist - The Rift War Saga
Terry Goodkind - Sword of Truth Series
Lyndon Hardy - Master of the Five Magics (1980), Secret of the Sixth Magic (1984), Riddle of the Seven Realms (1988). I beleive these are the only three books he ever wrote.
Mike Jefferies - Lore Master of Elundium Series
Robert Jordan - Wheel of Time Series
Katherine Kurtz - Camber Series and Deryni series
R. A. MacAvoy - Damiano Series
Patricai A. McKillip - Quest of the Riddle Master
Julian May - Saga of Pliocane Exile
Anne McCafferey - Dragon Riders of Pern Series
Melanie Rawn - Dragon Prince and Dragon Star Series
Fred Saberhagen - Empire of the East - Book or Sword Series and Book of Lost Sword Series
Margeret Weis and Tracy Hickman - Dragaon Lance Series (Tales, Chronicles and Legend) and Darksword Trilogy
Paul O. Williams - Teh Pelbar Cycle
I pretty much only read Sci-Fi/Fantasy, if you want to check out my Shelfari page and check my book ratings you should come up with some good stuff.
B Fisch - CA, USA
A few authors that I don't think have been mentioned in this thread yet...
Dan Abnett-Warhammer 40k Books (I like all his stuff, collected in Omnibus Editions)
Iain M. Banks-Culture Series
Stephen Baxter-Manifold Series, Destiny's Children Series
David Brin-Uplift Series
Julie E. Czerneda-Trade Pact Universe Series, Web Shifters Series
Gordon R. Dickson-Childe Cycle Series
David Drake-With the Lightnings Series
C.S. Friedman-(I like all her stuff)
Peter F. Hamilton-(I like all his stuff)
Jack McDevitt-Engines of God Series, Alex Benedict Series
Elizabeth Moon-Vatta's War Series
Richard Morgan-Takeshi Kovacs Series
Larry Niven & Jerry Pournelle-(Their collaborations are good)
Andy Remic-Combat-K Series
Alastair Reynolds-Revelation Space Series
Kim Stanley Robinson-Mars Series
Charles Stross-(I like all his stuff)
David Weber-Honor Harrington Series
Tad Williams-Otherland Series
Robert Charles Wilson-Spin Series
oh, and before you get into Gibson or any other Cyberpunk, you MUST read this first if you can find it... don't know if it's still in print.