YA recommendations:
Feed, by M.T. Anderson. It will blow you and your kids away with its prescience, since it was written in 2002 and yet captures the scary possibility (maybe already a reality) of advertising and social media gone wild.
The Absolutely True Diary of a Part-Time Indian, by Sherman Alexie. Wonderful, funny, very real.
Someone else mentioned Love That Dog by Sharon Creech. Such a fabulous book that just might change the way kids feel about poetry.
My youngest son is very much into Avi's books at the moment. If your kids are partial to historical fiction, the Crispin series is very good.
Me and Death: An Afterlife Adventure, by Richard Scrimger, is a fabulous read and very funny, about a young hoodlum who is killed and then gets a chance to come back armed with his knowledge of the afterlife.
Stop me, please, or I'll go on.