The Lord of the Rings, J.R.R. Tolkien. Classic fantasy by Tolkien, a skilled linguist.
The Foundation Trilogy, Isaac Asimov. An influential classic from the 1940s.
Dune, Frank Herbert An unusual book - mixture of epic science-fiction, some not entirely convincing ecology and carboard cutout villains make it something of a curates' egg.
Stranger in a Strange Land, Robert A. Heinlein
A Wizard of Earthsea, Ursula K. Le Guin
Neuromancer, William Gibson. Influential cyberpunk classic, though there are places where the writing shows some clunkiness.
Childhood's End, Arthur C. Clarke Strange books about Clarkes' favourite theme - stagnation or progress (in the form of spacetravel). More fantasy than science fiction, given an odd treatment of evolution.
Do Androids Dream of Electric Sheep?, Philip K. Dick Philip K. Dicks' classic work on "What is a human?". Admittedly weak in some aspects - the background seems a little odd given the history of a partial nuclear exchange and the rareness of animals - surely such scarcity of animals would be a sign of a deeply damaged and possibly inhospitable ecosystem?
The Mists of Avalon, Marion Zimmer Bradley Arthurian legend retold in terms of the decline of Celtic paganism and the triumph of Christianity. An odd book, given that her sympathy seems to be with Morgana and some of the things that Morgana did, but maybe she's trying to be ambivalent at the same time.
Fahrenheit 451, Ray Bradbury My first Bradbury novel and probably my last - the sickly feyness repels me and I'm not sure how the group of rebels at the end memorising books are supposed to achieve anything. The luddism seems misplaced - while Bradbury is condemning dumbing down, it's a product of human culture, not machines.
The Book of the New Sun, Gene Wolfe. Orac and I are going to have to disagree on this - it's a science-fantasy classic, IMHO.
A Canticle for Leibowitz, Walter M. Miller, Jr..
The Caves of Steel, Isaac Asimov. This is a bit stronger in characterisation of Elijah Bailey than many of the protagonists of his works.
Children of the Atom, Wilmar Shiras
Cities in Flight, James Blish
The Colour of Magic, Terry Pratchett Pratchetts fans aren't going to like this: I found this book leaden and plodding. His sense of humous just doesn't mesh with mine.
Dangerous Visions, edited by Harlan Ellison
Deathbird Stories, Harlan Ellison
The Demolished Man, Alfred Bester Odd book that has a quasi-Freudian explanation of the killers' motives. Somewhat dated.
Dhalgren, Samuel R. Delany.
Dragonflight, Anne McCaffrey
Ender's Game, Orson Scott Card
The First Chronicles of Thomas Covenant the Unbeliever, Stephen R. Donaldson.
The Forever War, Joe Haldeman
Gateway, Frederik Pohl
Harry Potter and the Philosopher's Stone, J.K. Rowling.
The Hitchhiker's Guide to the Galaxy, Douglas Adams. My type of humour!!!
I Am Legend, Richard Matheson
Interview with the Vampire, Anne Rice.
The Left Hand of Darkness, Ursula K. Le Guin
Little, Big, John Crowley
Lord of Light, Roger Zelazny
The Man in the High Castle, Philip K. Dick Classic alternate history novel.
Mission of Gravity, Hal Clement
More Than Human, Theodore Sturgeon
The Rediscovery of Man, Cordwainer Smith
On the Beach, Nevil Shute
Rendezvous with Rama, Arthur C. Clarke First encounter with an artifact.
Ringworld, Larry Niven
Rogue Moon, Algis Budrys
The Silmarillion, J.R.R. Tolkien Classic tragic fantasy
Slaughterhouse-5, Kurt Vonnegut
Snow Crash, Neal Stephenson
Stand on Zanzibar, John Brunner
The Stars My Destination, Alfred Bester Classic revenge fiction.
Starship Troopers, Robert A. Heinlein
Stormbringer, Michael Moorcock
The Sword of Shannara, Terry Brooks.
Timescape, Gregory Benford
To Your Scattered Bodies Go, Philip Jose Farmer - I remember starting this book, but quickly lost interest, so I can't claim I've read the whole thing.