@James

"I think it's a little vain to maintain a largely unread bookshelf."

On the contrary, the point of any library, including a personal one, is as a repository of information and entertainment. Why keep books you've already read, and won't read again?

I do this myself, admittedly*, but my "unread" shelves are rapidly catching my "read" shelves up.

* my new wife is going to cull my books for me if I don't do it myself soon. And I know I should. Why am I keeping "The Silicon Mage" by Barbara Hambly, for example? I'm not planning to read it again myself, and it's not one I'm keeping so my kids can read it. Not unless they've been really naughty.