Mish says:
Beowulf(anonymous)-just read it for AP English and fell in love with it
One Hundred Years of Solitude(gabriel garcia marquez)-reading it in AP English
Ishmael(Daniel Quinn)-read it last year, a great book that promotes a more "tough love" opinion on global poverty

maybe a few more fantasy, like The Once and Future King(T.H. White) or the Valdemar Series by Mercades Lackey.