"The Road to Serfdom" by Friedrich Hayek. You've probably come across people who think the Republicans are nazis but think that communism was great. Written during World War 2 by an Austrian, it describes how the differences between Socialism/Communism, and Fascism/Naziism are superficial. It also includes a primer on economics and why centrally-planned economies are so poor at allocating resources where needed.
"Eat the Rich" by P.J. O'Rourke. An economic treatise that will make your sides hurt. P.J. O'Rourke describes himself as a journalist who travels to foreign countries and trouble spots, and makes fun of them. Once you finish this one, you'll want to read "Parliament of Whores," "Peace Kills," and "All the Trouble in the World."
"Carnage and Culture" by Victor Davis Hanson. This book explores why Western cultures have kicked so much ass over the centuries. The author is a military historian, and he describes ancient and modern warfare in exquisite, gory detail.
"Basic Economics" and "Applied Economics," Thomas Sowell. All his books are great, but these two are quick economics tutorials. Read his others too, just know that they take longer.
"The Skeptical Environmentalist: Measuring the True State of the World" by Bjorn Lomborg. Lomborg is a Danish statistics professor. He set out to disprove statements by conservatives that the the environment isn't as bad as everyone says. To his surprise, he found that they're mostly right. This book is thick, but it has lots of figures, and he documents everything thoroughly. Lomborg is hated by the hairy armpit/soapophobe environmental types.