From a Sci-Fi mega-list I'm working on:
Hey,
I've seen a bunch of GAF threads where people are asking about what good sci fi and fantasy is out there. There are already a lot of resources on this site from past threads, so I decided to start compiling them into a big list so people have a central source to check things out. This is just the beginning, I expect it'll be updated, corrected and added to regularly for a while. Feel free to post really good Sci-Fi / Fantasy that I have missed and I'll add it. Where the author wrote novels in both genres and the recommendation for them is 'read everything!', they have usually only been listed in one genre.
LINKS
Hugo Award List and Runner Up List. Read all of these books.
http://en.wikipedia.org/wiki/Hugo_Award_for_Best_Novel
Arthur C. Clarke Award
http://en.wikipedia.org/wiki/Arthur_C._Clarke_Award
Nebula Award
http://en.wikipedia.org/wiki/Nebula_Award_for_Best_Novel
Top 100 Science Fiction Books (by online vote)
http://home.austarnet.com.au/petersykes/topscifi/lists_books_rank1.html
Next 100 Science Fiction Books (by online vote)
http://home.austarnet.com.au/petersykes/topscifi/lists_books_rank2.html
Top 100 Fantasy Books (by online vote, I do not agree at all with a lot of these)
http://home.austarnet.com.au/petersykes/fantasy100/lists_books.html
Next 100 Fantasy Books (by online vote, I still don't agree with most of these)
http://home.austarnet.com.au/petersykes/fantasy100/lists_books2.html
Top 100 Science Fiction Books (from David Pringle's book detailing his top 100 sci fi books from 1949-1984)
http://www.listology.com/list/david-pringles-best-100-science-fiction-novels
Prometheus Award (Libertarian Science Fiction Award)
http://en.wikipedia.org/wiki/Prometheus_Award
John W. Campbell Memorial Award
http://en.wikipedia.org/wiki/John_W._Campbell_Memorial_Award#Recipients
Locus Award for Best Novel (fantasy)
http://en.wikipedia.org/wiki/Locus_Award_for_Best_Fantasy_Novel
Locus Award for Best Novel (science Fiction)
http://en.wikipedia.org/wiki/Locus_Award_for_Best_Science_Fiction_Novel
Science Fiction (Just a sample and start-off point)
Iain Banks - Culture Series
Vernor Vinge - A Fire Upon the Deep; A Deepness in the Sky
Arthur C. Clarke - Childhood's End; Rama Series; 2001: A Space Odyssey; The City and the Stars
Philip Jose Farmer - Riverworld
Larry Niven - Ringworld (sequels are not as good)
Frank Herbert - Dune Chronicles
Isaac Asimov - Foundation Trilogy (and everything else he's written)
Alastair Reynolds - Revelation Space Series (and everything else he's written)
Orson Scott Card - The Ender Series
William Gibson - The Sprawl Trilogy
Robert A. Heinlein - Stranger From a Strange Land; The Moon is a Harsh Mistress; Starship Troopers (not like the movie, much better); (everything else he wrote)
Douglas Adams - Hitchhikers' Guide to the Galaxy; Starship Titanic
Joe Haldeman - The Forever War
Neal Stephenson - (everything he's written)
Peter Hamilton - Confederation Series; Night's Dawn Trilogy; Void Trilogy
Walter M. Miller, Jr. - A Canticle for Leibowitz
George Orwell - 1984
John Wyndham - The Chrysalids; The Day of the Triffids; The Midwich Cuckoos
Ray Bradbury - Fahrenheit 451
Philip K. Dick - Do Androids Dream of Electric Sheep )and everything else he wrote)
Dan Simmons - Hyperion Cantos
H.G. Wells - The Time Machine; The War of the Worlds
Carl Sagan - Contact
Kurt Vonnegut - Slaughterhouse Five; Cat's Cradle
Jules Verne - 20,000 Leagues Under the Sea; A Journey to the Center of the Earth; Around the World in 80 Days
Stephen Baxter - (everything he wrote, starting with the Xeelee Sequence)
Anthony Burgess - A Clockwork Orange
Daniel Keyes - Flowers for Algernon
David Brin - Uplift Series; Uplift Storm Series; The Postman; The Practice Effect; The Kiln People
Ursula K LeGuin - (everything she wrote)
Greg Bear - The Forge of God; Anvil of Stars; The Way Series; Darwin Series; Blood Music
E.E. Doc Smith - Lensman Series
Richard Morgan - Kovacs Series
James Blish - Cities in Flight Series
Frederik Pohl - Heechee Saga
Kim Stanley Robinson - Mars Trilogy
Gene Wolfe - Book of the New Sun Series
David Weber - Honor Harrington Series
Michael Crichton - Jurassic Park; The Lost World; The Andromeda Strain; Sphere; Timeline; Prey; State of Fear; Next
Roger Zelazny - Lords of Light; This Immortal; (everything he wrote)
Aldous Huxley - Brave New World
Harlan Ellison - (everything he wrote)
Charles Stross - Accelerando; (everything he wrote)
Stanislaw Lem - Solaris; The Cyberiad
Alfred Bester - The Stars My Destination
Gordon Dickson - Lifeship
Poul Anderson - The Boat of a Million Years; (lots of his other stuff)
Ben Bova - (everything he wrote)
Jerry Pournelle - (his best stuff usually is co-authored)
H. Beam Piper - Terro-Human Future History Series
Robert Charles Wilson - Spin; The Chronoliths
C.J. Cherryh - Cyteen; Downbelow Station; Rimrunners; Tripoint; Finity's End; (lots of her other stuff)
Piers Anthony - Biography of a Space Tyrant (totally different from his other work. These five books are fairly dark, very mature and extremely well written)
Julian May - The Saga of Pliocene Exile
Sean McMullen - Greatwinter Trilogy
Olaf Stapledon - Starmaker
Timothy Zahn - Thrawn Trilogy (Star Wars)
Spider Robinson - Deathkiller Trilogy; Stardance Trilogy