I like seeing fictional books since I can relate to the people writing them. If I enjoyed some of the fictional books that people talk about, then I'll go along with their non-fiction recommendations. Also, reading fiction shouldn't be treated like time wasted! I see that comment a lot by people who only read the non-fiction books, but I highly disagree with that thought. For another comment I guess.
One way to do that is to have different sections, one for fiction and one non-fiction. I'd love to see that here.
On that note, I've actually experienced that here, with some of the book recommendation threads, finding comments with books I also like and then reading the others. Always fun to talk to people who read the same as you.