1984- George Orwell
Fahrenheit 451- Ray Bradbury
Brave New World- Aldous Huxley
A Clockwork Orange- Anthony Burgess
As you can tell, I rather like dystopian fiction and those are some of my favorites, but let's see if I can come up with more…
Anything by PG Wodehouse (very English, so beware!)
Anything by Carl Sagan
Godel, Escher, Bach: An Eternal Golden Braid- Douglas Hofstadter
Silent Spring- Rachel Carson
Everything by JRR Tolkien
Anna Karenina- Leo Tolstoy
I think that's enough to keep a person busy with for a while…
I definitely recommend the Dragon King trilogy by Stephen H. Lawhead. The titles are In the Hall of the Dragon King, The Warlords of Nin, and The Sword and the Flame. Also the Dreamhouse series by Robert Liparulo, they're very original. :^D
Leviathan- Scott Westerfeld
Howl's Moving Castle-Diana Wynn Jones
The Mortal Instruments and their prequel series Infernal Devices-Cassandra Clare
If you are into Star Wars I recommend the Darth Bane trilogy as well as the Thrawn trilogy.
Hitchhikers Guide to the Galaxy series by Douglas Adams.
Anything by Chuck Palahniuk especially Fight Club and Diary.
Christopher Moore is a hilarious author, I just finished Lamb: The Gospel According to Biff, Christ's Childhood Pal.
The Hobbit by J.R.R Tolkein