I have a hundred plus books. To avoid being drowned in a sea of books, I do freecycle few of my books I've acquired over the past several years. I've also donated countless of books to the Webster Branch of the NYPL. The ones I no longer want.
I have a 3 shelf bookcase. On the bottom case are my art history and assorted reference books. On the shelf are my history books (on the left) and m science books (on the right). They're coincidentally separated by a dozen or so poetry books.
My favorite shelf is the third shelf where my fiction collection resides.
Interspersed into the whole potential alphabetical organization are misplaced books and magazines (most of the magazines are on the reference/bottom shelf). Oh yeah. A defunct Dell laptop as well.
The top of the book shelf are books I have yet to, my framed college degree, an autographed NY Yankees baseball I'm holding for a friend, a Russian nesting doll from Moscow (from Marietta's trip to Russia), a porceline reproduction of the Arc de Triomphe and a sewn Halloween pumpkin head attached to a wooden pedestal (up on my shelf 365 days a year).