I don't think there are any authors where I've read and loved absolutely everything. And it changes every so often - I still like Jack Kerouac, but he lost a lot of appeal after I turned 30. But here's a short list of faves:
George Saunders, Kurt Vonnegut, Luc Sante, Jonathan Lethem, Jim Shepard, Alice Munro, Herman Melville, George Orwell, Italo Calvino, Jorge Luis Borges, Naguid Mahfouz, Gabriel Garcia Marquez, Slavoj Zizek.