I'm just completing a re-reading of Ulysses twenty years after reading it as a student, and I'm amazed at how much I'm enjoying it. Yes, it's difficult and packed with allusions to literature, religion and philosophy that I've no idea about. But the sheer poetry of the writing, the humour and the inclusive passion for experience and existence, thought and emotion, have carried me over the difficult passages. 80 years after it was written there's still nothing to compare with Ulysses in its daring, scope and formal experimentation. If you want to understand the modern novel at all, start here.