I know how it is. You go to the library with your children and can't seem to find anything "new" that doesn't push the envelope a little too far. I don't personally read enought young adult books to recomend any new stories to you, but here are some suggestions that I hope will help.
* Read the classics. Classics to me are any book that is just as apealing today as it was when it came out 50+ years ago. Things like S.E. Hinton's The Outsiders and Lewis Carol's Alice's Adventures in Wonderland.
* Check out what's new in the Children's Department. Lots of Children's authors write wonderful stories that are just as wonderful and engaging for teens and adults as they are for children. A few of my favorites are K.G. Going and Kate DiCamillo. And don't forget those classics again! =)
*Check out this blog And others like it that give suggestions for books you like.