The Economic Naturalist: A truly great read, and just go ahead and buy it anyway. Robert Frank spent years teaching undergraduates about how to think like an economist, and it shows. An engaging, thought-provoking book that manages to entertain and inform at the same time, it is a truly great read.
The cartoon introduction to microeconomics: There are three books in this series, and all are worth reading. The cartoons are smart, funny and informative. Great way to start reading up on economics. If anything, not detailed enough – but it is a cartoon book, after all.
Freakonomics: This book has almost become the “Summer of 69” of introductory books on economics, and the worst part is that it isn’t even meant to be an introductory book about economics. But it is a very good book to read, as is its successor.
Reinventing the Bazaar: This is most assuredly not a light read, but it is equally so a great read. I hesitate to recommend this to students new to economics because it might put people off, but if you have the perseverance, the payoffs are huge.