My favorite book is either 100 Years of Solitude by Gabriel Garcia Marquez, or The Little Prince by Antoine de Saint Exupery.

But others I really love are:

Stranger in a Strange Land, and Glory Road by Robert Heinlein
Being and Nothingness by Jean-Paul Sartre
The Rules of Attraction by Bret Easton Ellis
The Giving Tree by Shel Silverstein ( I like a lot of his poetry, too. )
Leaves of Grass by Walt Whitman ( I should add him to my author's list...)
Choke, Fight Club, Diary, and Survivor by Chuck Palahniuk
Angels and Demons, The Da Vinci Code, and Digital Fortress by Dan Brown
Soul Kiss by Shay Youngblood
Dune by Frank Herbert

And more...
Oh, and right now I'm reading Less Than Zero by Bret Easton Ellis.