Twenty Thousand Leagues Under the Sea by Jules Verne was on my reading list for last summer, and I never got to it. I have some friends who've been telling me I need to read Jules Verne for a while now, so I went looking for it again and have just finished it. In a nutshell: his prose is gorgeous, but I think I need to read more of his books to appreciate his stories.
There's more to it than I just described, though. The plot thickens the closer you get to the end. As we go on, more is revealed (or more questions are raised) about the mysterious Captain Nemo. I personally became more attached as I went along to the narrator, Dr. Aronnax, and his two companions, Ned Land and Conseil. And sometimes, the wonder and beauty of the ocean that Verne describes is really astonishing.
So, it's not thick on plot, but still thick on motivations. The writing is lovely, the characters are deftly portrayed, moments of humor and moments of drama are played thoroughly and well. If you've got time to take a bite out of something really worth chewing over, you might want to pick up Verne.