Discipline and Punish by Foucault
Genealogy of Morals by Nietzsche
Structure, Sign and Playby Derrida
The Resistance to Theory by Paul de Man
Catch 22 by Joseph Heller
The Hitchhiker's Guide to the Galaxy, and all subsequent works by Douglas Adams
That Book About the Guy who Could Do Whatever by Mike Moorcock
Those Other Books about that Guy who could do Whatever by Robert Jordan
Dune, again, because every time I see something new, whether I like it or not.
Penis. I just threw that in there because I'm reading about two-dozen contemporary fiction writers, and all of them seem preoccupied with the same thing. Apparently this is how you sell books nowadays.