Like Sloane Crosley, we currently have no bookshelves in our house. However, unlike Crosley, we intend to get some, rather than doing as she does: perching books on all available surfaces including the supposedly decorative mouldings that run around the walls of her apartment.
In a piece for the New York Times, she also talks about her organisation strategy: books are arranged not alphabetically or by size, theme or colour of spine, but as a "sentimental library", one that is "characterized by memory and association". A useful pointer, perhaps, for when I eventually get around to getting my books out of boxes and toppling piles and into some vague semblance of order.
(Thanks to Adam for the link.)