Tom's Semi-Official and Totally Incomplete Classics of Sci-Fi List
I told ruthette  that if she'd draw me up a list of good literary classics I'd reciprocate with a list of science fiction classics. The list that follows is my attempt to do that.

This is a tricky sort of thing to accomplish, and this list is by no means comprehensive. First of all, it's basically limited to books I have actually read with only one or two exceptions. Secondly, if I did read it, I had to have enjoyed it. Third, I've not included much "literary" science fiction. 1984 is considered SF and usually makes these lists, but it's honestly literary in execution and intent, so I've left it out.

Then of course there's the thorny problem of the kind of sci-fi that a geek would consider a classic versus the kind that everyone ELSE would consider a classic. A geek would tell you that Iain M. Banks' Excession is gee-whiz cool or that you just HAVE to read the hard sci-fi classic Mission of Gravity, but those are books that are classics on technical rather than literary merits and might be uninteresting or even impenetrable to a casual reader. So I've left those out.

On the flip-side, some "classics of sci-fi" are just fun, probably way too fun to pass in polite company. Robert A. Heinlein and Douglas Adams are two authors who would probably fall into this category. But you know what? I have nothing against FUN, so I've left them in.

So, here is my completely arbitrary yet totally definitive list of THE CLASSICS OF SCIENCE FICTION! (tm)

Dune, Frank Herbert
Well, I guess you have to mention Dune. It's pretty good, although it can be a lot to unpack in one read. It leaves you hanging a bit, but steer clear of the sequels.

The Foundation Trilogy, Isaac Asimov
Asimov's seminal work unfolds with logical precision. The "trilogy" is actually a series of novellas set in a distant future where history can be mathematically predicted. Deus ex machinas ensue.

A Canticle for Leibowitz, Walter M. Miller
I've never gotten around to reading this, but I really need to. Everyone always lists it as a classic. Apparently it's the ultimate post-apocalyptic novel.

The Left Hand of Darkness, Ursula K. Le Guin
It's a buddy comedy featuring trans-gender aliens! On this planet, people change sex throughout their lives. Le Guin is a very literary author and this is actually a beautiful story of friendship.

The Dispossesed, Ursula K. Le Guin
This is one of my all-time favorite novels, but it's much more 'literary' than most sci-fi. A group of radical dystopians make their home on a desolate moon while below their estranged kinsmen live in extravagant excess. A scientist tries to bridge the gap between the two worlds.

Childhood's End, Arthur C. Clarke
It's the end of our species as we know it, but we feel fine! The true masterpiece of the original author of 2001: A Space Odyssey.  The ending is inevitable and sad.

Ringworld, Larry Niven
Imagine if there was a world like earth, but it was shaped like a ring. OK, I think you've got it.  A fun alien-world-exploration novel.

The Man in the High Castle, Philip K. Dick
I haven't actually read this one, but I've read other Dick books. He's weird, but good. People are always making movies out of his ideas. This is his most well-regarded book.

Farenheit 451, Ray Bradbury
Chances are good that you've read this, but it IS one of the all-time classics.

The Moon is a Harsh Mistress, Robert A. Heinlein
A colony on the moon throws off the brutal yoke of Earth rule! Not particularly deep, but a crackin' good yarn.

Neuromancer, William Gibson
The father of cyberpunk, um, gives birth? It's your new future, where everybody's on drugs and corporations rule the world. See what all the fuss is about.

Hyperion, Dan Simmons
A group of travellers tells each other their stories, slowly unfolding an interstellar conspiracy against humanity. But one of them is a spy!  Dark, brilliant and epic.

Ender's Game, Orson Scott Card
In a desperate war with implacable aliens, bright children are trained for military command at the Battle School. Boy genius Ender will show all his bullying classmates when he's picked to join.  Sibling rivalries are portrayed all too believably.

Speaker for the Dead, Orson Scott Card
Boy genius is older, wiser and sadder.

Red Mars, Kim Stanley Robinson
One of the best stabs at writing a future history of the colonization of Mars.

Doomsday Book, Connie Willis
The thirteenth century turns out to be a lousy place to live OR visit when a grad-student from the future unwittingly gets stuck there. Surprisingly touching.

A Fire Upon the Deep, Vernor Vinge
The galaxy is divided into zones - in the inner zones the speed of light is a barrier and everything sucks. The outer zones are where the physics are easy and the intergalactic civilizations party...

A Deepness in the Sky, Vernor Vinge
A prequel to Fire Upon the Deep. Embattled and stranded, two human factions wait breathlessly for a race of intelligent spiders to advance to the point where they can leave their homeworld and resolve the conflict.  Complex and cool.

Downbelow Station, C.J. Cherryh
A distant space station flooded with refugees becomes a contested focal point in a bitter interstellar war.  Intense and touching.

The Hitchhiker's Guide to the Galaxy, Douglas Adams
It's very funny, and it begins with the destruction of the Earth.

Snow Crash, Neal Stephenson
In the first few pages we meet a sword-wielding ninja hacker pizza deliveryman in a sportscar. It gets weirder from there.

The Forever War - Joe Haldeman
Imagine if a hippy peacenik wrote a book about interstellar war. It would probably be exactly like this.  I'm not the biggest fan but a lot of people like it.

Look to Windward - Iain M. Banks
The benevolent Culture tries to push less enlightened civilizations towards peace and progress. They deal with the consequences of two separate failures that resulted in war - one recently, one hundreds of years ago.  Features cat-like aliens!</b>