Our homeschooling was heavily literature-based, and the morning read-alouds were some of my favorite moments in the day. It was productive, yes, but that didn't take away from the fact that it was time spent together when the kids got to simply relax while still doing school.
Narnia is amazing. So are the Little House books—our boys got such a kick out of Almanzo Wilder's appetite when he was a young boy!—and many others they still quote. Good historical fiction will cement the information much more solidly than most dry textbooks, and fantasy or science fiction encourage such out-of-the-box creativity. I love it.