For books I and my girls are fans of Measle Stubbs
http://www.ianogilvy.com/measle.htm
As for the teenies,dear Crumbs, i can only talk for female teenies
- vouchers to get their nails or hair done
- if you have a well filled wallet,there's a craze to have your smile
embellished with a small diamond at the dentist, a voucher for that
- tickets to a pop concert
- treat girls and mum to a weekend or day in a spa or similar
instituion whilst u take the boys for a boys day out and go go-carting or
so with them
- my gals don't mind getting vouchers from clothes stores,afer all they can never have enough clothes and shoes when they are teenagers

so C&A,H&M,Tally Weill,New Yorker,ORSAY and such are a good bet that they will like it and for other embellishements CLAIRE'S is a good bet too.
well gott a go and pu the fire on under my cauldron to feed my teenagers but will think of more ideas