I read more detective/crime/mystery books than any other genre and we have a considerable number of such books in our home.
However, I'm an eclectic reader and have and read books from many other genres. I read fantasy, children's books, romance, women's literature, chic lit, humour, some biographies, general fiction, young adult books to name but a few.
So yes, I tend to mix it up and swap from genre to genre depending on my mood. However, if I'm reading a series (like at the moment I'm re-reading Harry Potter) I do stick to the series and read from beginning to end even when it's a very long series.