Exactly. Unless you make notes (most) books are instantly replaceable. I have one shelf of my absolute favourite books & dvds (so I can loan them out). Plus a kindle for everything else.

The reality is knowledge is even cheaper than food these days, and books are backbreaking whenever you move. A rational cost/benefit analysis will tell you to rid yourself of books before clothes. A favourite shirt is nearly irreplaceable, a favourite book can be replaced in a day.