Being a fan of sci-fi, and wanting to expand my own reading list, I thought it would be helpful to tally the results and preserve them here for future reference.

I've also included selected quotes from the comments, as well as my own notes on the books I've already read.

PS: All book images in this post are copyright Amazon, and were retrieved using my Big Book Search Engine.

So, without further ado, here are the Greatest Sci-Fi Books of All Time, ordered by upvote count:book cover



Frank Herbert - 1965

"There's a reason it's the global top selling science fiction book of all time." - NibblyPig


If you have a chance, track down the excellent full cast audiobook (unabridged!) released in 2007. It's more like a radio play than a traditional audiobook, and highly enjoyable.



The Hitchhiker's Guide to the Galaxy



Douglas Adams - 1979

"I really love the cool combination of humor, philosophy, and sheer nuttiness of the entire series." - Scarbrow


To be honest, while I liked this book, I found the jokes somewhat less funny than expected.


Ender's Game



Orson Scott Card - 1985

"I've never felt so connected to a character within the first 50 pages as I did with Ender." - endtype


One of those books you'll either love or hate. It probably depends on how successful your grade-school social life was...



Foundation Trilogy



Isaac Asimov - 1942

"I was literally in awe at the way Asimov wrote... The entire thing was so extremely well thought-out and well-written." - Scarbrow




Hyperion



Dan Simmons - 1989

"...One of, if not the most bad arse and brilliantly thought out monsters in science fiction history." - bluntstick


The first book in the excellent Hyperion series. An interesting collection of "how we got here" stories, told from multiple viewpoints (some of which you'll enjoy more than others). It largely serves as the setup to the second book, Fall of Hyperion, which follows a more traditional narrative structure.


Neuromancer



William Gibson - 1984

"Without it, there is no Matrix." - HenryKillinger

My personal favorite, and perhaps the first real sci-fi novel I read. I revisited it many years later in the form of an audiobook read by the author himself (complete with soundtrack)! The Gibson-narrated version is no longer for sale, but fortunately, it's easy to find on Google.



Snow Crash



Neal Stephenson - 1992


Ever wonder where the term "Avatar" came from? The concepts in this book may not hold the same novelty they once did, but if everything in Snow Crash seems familiar, it's because Stephenson inspired a generation of internet nerds to turn his ideas into reality.

I'm looking forward to Neal's new book.



Childhood's End



Arthur C. Clarke - 1953

"The most epic and incredible ending in any story ever told. Pure greatness." - BukkRogerrs



The Forever War



Joe Haldeman - 1974

"Short, but fantastically well executed. It might be so good, in part, because it's short. He didn't beat the thing to death like so many other authors end up doing." - jfilling



Ringworld



Larry Niven - 1970

"The science is almost the main character and the humans & aliens happen to be there to explain it to you." - UptownDonkey



Do Androids Dream of Electric Sheep?



Philip K. Dick - 1968

"The sci-fi is almost a backdrop to much more human and emotional story." - BiohazardBlaze


Of course, this eventually became one of my favorite films: Blade Runner.


Stranger in a Strange Land



Robert A. Heinlein - 1961

"I wish I'd read this at 12, and not 29 as it turned out. I think I would've turned out a far better person." - shrevid



Starship Troopers



Robert A. Heinlein - 1987

"The movie and book are different in every way except for the fact that they both involve a war with bugs." - Ragnrok

"... and they're both freaking awesome." - teletoes



The Culture Series



Iain M. Banks - 1987

"The ships make it worth it on their own, their Minds are some of the best drawn characters ever. Fantastic writer..." - rthrtylr

I'm currently deep into the second novel, Player of Games, which generally receives higher recommendations, but in my experience, Consider Phlebas was a fine starting point.



A Canticle for Leibowitz



Walter M. Miller, Jr. - 1960

"One of the rare books where I spent days afterwards thinking about it." - metastable2



Rendezvous with Rama



Arthur C. Clarke - 1973

"I was a Catholic until I read those books..." - PLJNS



Pandora's Star



Peter F. Hamilton - 2004

"A really cool universe with a plot you can't put down." - kodemizer


I've owned a copy of this for years, but never made it past the first chapter...


The Mote in God's Eye



Larry Niven & Jerry Pournelle - 1974

"Space Political Struggle, so good." - ev0l_yeti



The Stars My Destination



Alfred Bester - 1956

"There's something enthralling about a man driven by PURE RAGE who will stop at nothing to achieve his goal." - MaunaLoona



Altered Carbon



Richard K. Morgan - 2002

"There is something to be said for a combination of "hard-boiled detective story", sci-fi, a bit noir and a twist of dystopia." - cupofcocoa



Red Mars



Kim Stanley Robinson - 1993

"The way he weaves together technology, politics, and personal stories is absolutely unparalleled." - msingerman



2001: A Space Odyssey



Arthur C. Clarke - 1968

"The book ending was much better IMO. Well, unless you're really stoned, then the movie is awesome!" - Rediting



Contact



Carl Sagan - 1985

"One of the few works in this thread that's truly more sci-fi than fantasy. A brilliant, brilliant novel." - NotJohnBoy



The Sirens of Titan



Kurt Vonnegut, Jr. - 1959

"It's deeply disturbing in a gentle manner." - ZombieLobotomy


Vonnegut is the master when it comes to examining the absurdity of human behavior. He manages to expose our collective terribleness in a way that's both hilarious and depressing.


I, Robot



Isaac Asimov - 1950

"Once found a copy on the beach on holiday. Started reading and could not put it down until i had finished it... got sunburn as a result. Thanks Asimov. " - DubiumGuy



The Left Hand of Darkness



Ursula K. Le Guin - 1969

"Ursula Le Guin is one of my personal heroes... fantastic author, thinker, idealist." - pbeunttz



Revelation Space



Alastair Reynolds - 2000

"...Whoa, so dark in style! Reminded me of dirtier cyberpunk stuff from the nineties." - Rxke



Old Man's War



John Scalzi - 2005

"Highly recommended. Other books might be more cerebral or philosophical, but damnit these books are really fun to read." - NorthernBoreus



Anathem



Neal Stephenson - 2008


Sometimes, I wish I could live in this book. Don't be put off by Anathem's monstrous size or strange vocabulary, this is a rich and rewarding experience.

"It was one of those books that made me sad when I finished it because I could never read it for the first time again. A modern masterpiece in my opinion." - spartankope


Armor



John Steakley - 1984

"In a personal depiction of self-torment and violence; a man willingly turning himself into a sociopath, into The Engine..." - c4tch



Oryx and Crake



Margaret Atwood - 2003

"Highly recommended for readers interested in near future dystopias." - Pimpernickel


As a Canadian, I tend to avoid Margaret Atwood for the same reasons I avoid Celine Dion or Nickelback... However, I had no idea she wrote sci-fi!


Fahrenheit 451



Ray Bradbury - 1953


There's a really incredible audiobook version of Fahrenheit 451 read by the author himself (with zeal!). Track it down, you won't regret it.


A Fire Upon The Deep



Vernor Vinge - 1992

"Definitely the best portrayal of how a truly galactic society would work..." - KrytikalMasz



Quarantine



Greg Egan - 1992

"Incredible... I urge anyone interested in hard scifi to read Egan. DO IT " - EarlGreyGoo



The Chronicles of Amber



Roger Zelazny - 1970

"I think these are more fantasy than scifi but the original 5 books were my all time favorites growing up." - not-throwaway



Heir to the Empire



Timothy Zahn - 1991

"This was by far the best Star Wars novel made." - Herebec



The Book of the New Sun



Gene Wolfe - 1980


"Was recommended this by a friend and it blew my mind, unlike anything I'd ever experienced and I've read most of the books mentioned..." - semperviren