That's difficult because there are certain subjects in non-fiction that I really enjoy and I'm just as selective about the types of fiction I enjoy. And then every so often an odd ball from a genre/subject I wouldn't normally enjoy comes along and turns my preferances on their heads. And it really depends on the mood I'm in which I'm more inclined to go for. I guess usually fiction, but only by a little and only certain genres (I'll always pick a science book over a sappy romance novel).
What would you rather prefer for dinner - danish meat balls in curry with apples and celery served with rice and cucumber salad or russian cold soup okroshka?