In chronological order
Aldous Huxley's doors of perception, William Blake's marriage of heaven and hell, Goeth's faust, Fredrich Nietzsche's birth of tragedy, Robert Anton Wilson's prometheus rising, Ramon Sender's seven red sundays, Barbara Meyhoff's peyote hunt, Herman Melville's moby dick, Leopold von Sacher-Masoch's legacy of cain, Walt Whitman's leaves of grass, Celine's journey to the end of the night, Isabel Fonseca's bury me standing, Octavio Paz's labyrinth of solitude, Dominique Lapierre's or I'll clothe you in mourning, William Bateson's ecology of mind, Eric Fromm's selected works of karl marx, PKD's we can build you, Bukowski's women, Jorge Borges' collected nonfictions, Lawrence Durrell's black book, Henry Miller's black spring and both tropics, Ernest Hemmingway's for whom the bell tolls, old man and the sea and a sun also rises, Fernando Pessoa's book of disquiet, Cormac McCarthy's blood meridian and suttree, William Faulkner's the sound and the fury and as I lay dying, Kahlil Gibran's the prophet, Kurt Vonneguts cat's cradle, Garcia Marquez's autumn of the patriarch.
Forgot Ed Abbey's desert solitaire, Terry Mort's reasonable art of fly fishing, and of course all of Poe's short stories.
Sartre's no exit was good, too. And Dostoyevsky of course, but then georg lucaks or bifo berardi or nokolai golgol and pushkin's works would have to be brought up as well as a host of others... not so lifechanging as the above, though.
Was very surprising to see Henry Miller already mentioned here, browsing up after posting. Almost nobody I bump into has even heard of him, and yes black spring was terrific, and would totally recommend his greece travelogue as well 'collussus'.