Some years at my school I buy a bunch of different $10 -$15 gift cards to Subway, Starbucks, Ihop, Dillons, WalMart, etc and let everyone pick what they want. I keep what is left over and give them away during the year.
If I was a Librarian and somebody gave me a present that had to do books, I would be all pissed off.
I'd be pissed off quietly, but all pissed off nonetheless.
Assuming they are female, you could get them decorative scarves like the one linked. The clerk at Pennys can help you pick them out. Women usually really like scarves, but sometimes have no use for them. If the latter, it is an item they can easily "re-gift".
You could get them each an eBook, but they might not like that since eBooks tend to put them out of business.