From here (explanation; criticism of list [edit: see also my comments at the bottom of the post]).
I am incapable of reading lists that are bolded/starred/whatever to represent certain things without constantly scrolling back up to look at the key. So text-only for you!
[Edit: at Chad's request, I have bolded the books & authors to make them stand out; the bold has no other meaning.]
"Unread" books without further comment are books that I don't have any opinion on.
The Most Significant SF & Fantasy Books of 1953-2002
- The Lord of the Rings, J.R.R. Tolkien
Not only have I read it and loved it, I'm re-reading it (still! honest!).
- The Foundation Trilogy, Isaac Asimov
Unread; somehow missed it when I was reading Asimov, and now I doubt I would like it.
- Dune, Frank Herbert
Unfinished; I recall trying the first few pages and putting it down, bored.
- Stranger in a Strange Land, Robert A. Heinlein
Unread, no desire to read.
- A Wizard of Earthsea, Ursula K. Le Guin
Read, barely remembered.
- Neuromancer, William Gibson
Read, unimpressed.
- Childhood's End, Arthur C. Clarke
Read, liked it, don't know how it would hold up.
- Do Androids Dream of Electric Sheep?, Philip K. Dick
Read, barely remembered (and that was in college; the movie stuck more, and I didn't even really like it).
- The Mists of Avalon, Marion Zimmer Bradley
Read, disliked.
- Fahrenheit 451, Ray Bradbury
Read for school, no opinion.
- The Book of the New Sun, Gene Wolfe
Unread, might read.
- A Canticle for Leibowitz, Walter M. Miller, Jr.
I might have read this. I'm not sure.
- The Caves of Steel, Isaac Asimov
Read, as are the rest of the Robots stories (okay, until whatever point it started explicitly crossing over with the Foundation series).
- Children of the Atom, Wilmar Shiras
Unread and unheard of.
- Cities in Flight, James Blish
Unread.
- The Colour of Magic, Terry Pratchett
Read, and while it's not that good on its own, it was the start of my binge on Discworld (summer, college, Boston Public Library) which has matured into a long and happy relationship.
- Dangerous Visions, edited by Harlan Ellison
Possibly read some, unsure.
- Deathbird Stories, Harlan Ellison
Unread, probably.
- The Demolished Man, Alfred Bester
Unread.
- Dhalgren, Samuel R. Delany
Unread, scared to try it.
- Dragonflight, Anne McCaffrey
Read, and a lot more besides, which is embarassing now.
- Ender's Game, Orson Scott Card
Read, will never re-read for at least two reasons.
- The First Chronicles of Thomas Covenant, Stephen R. Donaldson
Read, though I really don't know why as I didn't enjoy it.
- The Forever War, Joe Haldeman
Read, don't recall much about it.
- Gateway, Frederik Pohl
Unread.
- Harry Potter and the Philosopher's Stone, J.K. Rowling
Read, hoping book 7 doesn't suck.
- The Hitchhiker's Guide to the Galaxy, Douglas Adams
Read, and the next three (in my universe there was no fifth book).
- I Am Legend, Richard Matheson
Unread.
- Interview with the Vampire, Anne Rice
Unread, no desire to read.
- The Left Hand of Darkness, Ursula K. Le Guin
Read when too young, should read again.
- Little, Big, John Crowley
Read, enjoyed, have no desire to read anything else by him.
- Lord of Light, Roger Zelazny
Unread, but I intend to read it.
- The Man in the High Castle, Philip K. Dick
Unread, unlikely to read.
- Mission of Gravity, Hal Clement
Unread, might read.
- More Than Human, Theodore Sturgeon
Unread.
- The Rediscovery of Man, Cordwainer Smith
Unread.
- On the Beach, Nevil Shute
Unread.
- Rendezvous with Rama, Arthur C. Clarke
Read, enh.
- Ringworld, Larry Niven
Read, enh.
- Rogue Moon, Algis Budrys
Unread.
- The Silmarillion, J.R.R. Tolkien
Read, loved parts of.
- Slaughterhouse-5, Kurt Vonnegut
Unread, unlikely to read.
- Snow Crash, Neal Stephenson
Read, enjoyed most of it but nevertheless was put off further Stephenson even if people swear he does better endings now.
- Stand on Zanzibar, John Brunner
Unread.
- The Stars My Destination, Alfred Bester
Unread.
- Starship Troopers, Robert A. Heinlein
Unread, no desire to read.
- Stormbringer, Michael Moorcock
Unread, no desire to read.
- The Sword of Shannara, Terry Brooks
Read. Well, the second one wasn't a waste of time . . .
- Timescape, Gregory Benford
Unread.
- To Your Scattered Bodies Go, Philip Jose Farmer
Unread.
[Edit: in addition to the criticisms in Sherwood Smith's post, on thinking about this further, I have more: where is urban fantasy (War for the Oaks), fantasy of manners (Swordspoint), the new space opera (Iain M. Banks, Ken McLeod)? Standard biases for such a list, I guess: toward older, toward hard sf, toward male authors.]
More interestingly: look into your crystal balls, dear readers, and predict the most significant books since 2002. I'll start: Jonathan Strange & Mr Norrell by Susanna Clarke.