The context of these book titles appearing in comments might skew the results. Ulysses is high up on the list, but the source comments have a lot of people using it as an example of a lengthy, difficult book.

I read a lot, but if I'm going to use a book to make a point or example in a comment, which will be read by someone I don't know, I'll reference a well-known book that most people have heard of, even if it was just from 9th grade English class, instead of something more obscure.