In defence of James Joyce
The Dubliners is a collection of simple, well-written stories.
A Portrait of the Artist is also deceptively simple, really, but with a much stronger poetic sensibility - not only the ideas, but the way the words describing the ideas fit together is becoming more important, and he's starting to see hwo the two combine. Also, the best description of the terrifying effect of a Catholic education I've ever read - it's worth it for that alone.
Ulysses: First, this book has been ruined for many by being studied academically. Nothing kills the enjoyment of literature quite like literary criticism. Second, it is essentially a poetry collection. You can linger and savour individual allusions, paragraphs and sections as more-or-less self-contained wholes. I think if you embark on Ulysses - I only finished it second-time-round - don't feel under pressure to finish it. Take something from each section. Read other books while you read this one - in one big lump, it's quite hard to digest, but as a series of snacks, it isn't. I think the perfect way to read Ulysses would have been in the monthly serialisation that was how it first appeared. I was inspired by Ulysses when I first started trying to write fiction. It showed me that there are other ways of doing things - that you're allowed to do absolutely anything you like with that page. Maybe it is more of a writer's book in that sense.
Finnegan's Wake. I didn't get past about page 10 of this book, so I cannot defend it.