Reddit mentions of The Terrorism Trap: September 11 and Beyond

The Law by Frederic Bastiat (awesome, short, soooo many quotable quotes)

Healing Our World by Dr. Mary Ruwart (old version available free)

Haven't read any of his books (have listened to many lectures and radio show), but something by Harry Browne should do quite nicely. I've heard great things about Why Government Doesn't Work

Myths, Lies, and Downright Stupidity - John Stossel (do check out his excellent Fox Business show "Stossel" on hulu.com, and look for his old 20/20 specials on libertarianism - they're fantastic)

good economists: Peter Schiff, Walter Williams, Thomas Sowell, Walter Block

You might be better off waiting til you get more comfortable with libertarianism, but G. Edward Griffin's Creature From Jekyll Island is a must read. It's more about the monetary system and the Federal Reserve than libertarianism in general though.

I haven't read anything that makes a good argument against libertarianism, but can recommend a guy who makes a seemingly good argument against capitalism and for socialism - Michael Parenti. I haven't read any of his pro-socialist books (but have one on foreign policy called The Terrorist Trap which is quite good and very short. Libertarians and socialists tend to agree on not inviting war and not waging war). But I have listened to his pro-socialist lectures - they're well delivered and impassioned and a person who didn't know any better would easily be tempted. They're worth listening to to use his arguments and twist them to actually make the case FOR libertarianism. He'll use some faulty facts/data that leftists typically do such as "Hoover was an ardent free-market advocate and we can blame him and capitalism for causing the Great Depression" (we can blame him for the depression all right (prolonging it, to be specific), not b/c he was a capitalist but b/c he really started all the policies that FDR continued when he got into office)