In no special order (and probably not complete):

John Ronald Reuel Tolkien's Hobbit + Lord of the Rings
Douglas Adams' Hitch Hiker's Guide to the Galaxy (all 5 volumes of the 4 -volume trilogy)
Douglas Adams' Dirk Gently's Holistic Agency
Douglas Adams' Long Dark Teatime
George Orwell's 1984
George Orwell's Animal Farm
Herbert George Wells' Time Machine
Herbert George Wells' War of the Worlds
Herbert George Wells' Invisible Man
Ray Bradbury's Fahrenheit 451
Aldous Huxley's Brave New World
Alex Haley's Roots
Robert Louis Stephenson's Treasure Island
Daniel Defoe's Robinson Crusoe
almost all books by Jules Verne (in their German translation)
Michael Crichton's Andromeda Strain
Tom Clancy's Hunt for the Red October
almost all books by Karl May (I was young, I needed the money ;-))