Alexandre Dumas. Between Three Musketeers, Count of Monte Cristo, and The Black Tulip you have some of the most defining novels I've read. I like Jules Verne too, but not nearly as much as Dumas. French literature in general seems to rub me the right way.
Terry Pratchett comes in second for Discworld, especially everything to do with Rincewind or the Night Watch or the Wizards or the Witches.

Steinbeck. I loved Cannery Row and The Graqes of Wrath is another one of my favorites.
Travels With Charlie in Search of America is my favorite Steinbeck book. A lot of people seem to not know about it. Even my college English teacher hadn't heard of it.
