Science Fiction:
Isaac Asimov's Foundation Series
Isaac Asimov's Robot Series
Star Trek Fiction, usually those of the old crew
Usually anything by C.J. Cherryh
Anything by Robert Anson Heinlein
Arthur C. Clark, especially the 9 Billion Names of God
Frank Herbert's Dune series and other books.
Edgar Rice Burroughs, especially the Illustrated Man
John Varley
The "Ship" series
The Time Patrol
Fantasy:
J.R.R. Tolkien's The Lord of the Rings
Raymond Feist's The Sorcerer's Apprentice, also known as the SerpentWar Saga and the Riftwar Saga
Robert Jordon's The Wheel of Time
The Chronicles of Narnia
Frederick Pohl
Stephen Kurtz
The High Deryni Series
Dark Gothic Series Include:
Anne Rice's The Mayfair Witches,
tied into Interview with a Vampire and the Vampire Chronicles
Dracula
Twilight
The Matrix
Underworld Series