get out of (literary) jail free

Sometimes I feel bad about not reading enough "capital-L" literature.

Then I remind myself that as a mad teenager I once read James Joyce's Ulysses from cover to cover, which surely earned me enough enduring lit-cred to never have to read again.

Everyone should have a book like that, I reckon. Do you? If so, what is it? Gravity's Rainbow? War and Peace? The Grapes of Wrath?