Reddit mentions of Thinking About GIS: Geographic Information System Planning for Managers

You've already had some good suggestions, which I'd suggest following. I have a BA in geography and even after school found these interesting reads.

Cultural and Historical Geography

Eratosthenes' "Geography"

The World of Gerard Mercator: The Mapmaker Who Revolutionized Geography

Guns, Germs, and Steel: The Fates of Human Societies

Race And Culture: A World View

Technical, GIS, Cartography

How to Lie with Maps

Thinking About GIS: Geographic Information System Planning for Managers

An Introduction to Geographical Information Systems

I know most of these won't be of much use with a BS degree, but gives you a good foundation for thinking geographically. For the more science aspects; a good understanding of physics, chemistry, and to a lesser extent biology, will really give you a leg up when starting out.