Listen to me, not to Oprah! Get your modern American literature here...
William T. Vollmann: You Bright and Risen Angels, Rising Up and Rising Down (7 volumes if you can, 1 volume if you must), Imperial
Don Delillo: White Noise, Mao II, Underworld, Libra
Thomas Pynchon: Crying of Lot 49, V, Gravity's Rainbow, Mason & Dixon, Against the Day (okay, I'd really recommend it all, so add Vineland and Inherent Vice)
Cormac McCarthy: Blood Meridian, The Orchard Keeper, No Country for Old Men
Philip Roth: American Pastoral, Portnoy's Complaint, Zuckerman Unbound
Saul Bellow: Herzog, Seize the Day, Adventures of Augie March
John Updike: Rabbit novels
John Irving: A Prayer for Owen Meany, Water Method Man
Vladimir Nabokov: Ada, Pale Fire, Lolita, Pnin
Kurt Vonnegut: Slaughterhouse Five, Sirens of Titan, Galapagos, Breakfast of Champions, Player Piano
Tim O'Brien: Going After Cacciato
William Gaddis: The Recognitions, Agape Agape
Jack Kerouac: On the Road, Visions of Cody, Big Sur
William S. Burroughs: Western Lands, Naked Lunch, Nova Express
Okay, I was just venting a little bit...