Those asterisked I have read. **means I can’t remember if I read it long ago or not.
1* Herbert, Frank : Dune (1965)
2* Card, Orson Scott : Ender’s Game (1985)
3* Asimov, Isaac : The Foundation Trilogy (1953)
4* Simmons, Dan : Hyperion (1989)
5* Le Guin, Ursula K. : The Left Hand of Darkness (1969)
6 Adams, Douglas : The Hitchhiker’s Guide to the Galaxy (1979)
7* Orwell, George : Nineteen Eighty-Four (1949)
8* Gibson, William : Neuromancer (1984)
9* Bester, Alfred : The Stars My Destination (1957)
10** Bradbury, Ray : Fahrenheit 451 (1953)
11* Heinlein, Robert A. : Stranger in a Strange Land (1961)
12 Heinlein, Robert A. : The Moon Is a Harsh Mistress (1966)
13* Haldeman, Joe : The Forever War (1974)
14* Clarke, Arthur C. : Childhood’s End (1953)
15* Niven, Larry : Ringworld (1970)
People obviously voted for their favourites from their youth and not in terms of literary quality.
The only one of them I would put in a top ten is the Le Guin. My memory of that is that it was one of the best books I have ever read, never mind just SF books. It was a long time ago, though.
And where is Robert Silverberg on the Locus list? Shameful.