I've been reading Death from the Skies by Phil Plait (The Bad Astronomer) and plan to add it to my classroom bookshelf for my students.  I've got a collection of 20 or so books that my students can borrow, including The Demon-Haunted World (Carl Sagan), The Elegant Universe (Brian Greene), Chaos (James Gleick), Richard Feynman's autobiographies, A Brief History of Time (Stephen Hawking), and many others I can't think of right now.  Any other recommendations?