Recently I did some purging of my books -- about 70-80, I'd say. Maybe more, maybe less.
The process was painful ("Will I ever read this book during the course of my lifetime? Is there still a chance I'll need to reference The Dialectic of Enlightenment? If I haven't read The Magic Mountain or The Death of Virgil yet, will I ever get to them, especially since I'm currently reading something like eight books and I haven't finished one in several months?"). But, reader, it was necessary.
Our house is small and we're running out of room. There are still two large bookshelves in the twins' bedroom. And there are bookshelves in our bedroom, the living room, and the den, as well as several boxes of books in my mother's garage.
More removal/purging is imminent. What I don't get rid of, I'll be boxing up, then storing in our attic, where hopefully the heat won't do any damage.
There will still be lots of books. Just not as many.
The good: According to a recent study, having lots o' books around the house (the more, the better) correlates to how many years of schooling a child will complete.