My problem with the Libertarians is the same issue I have with Communists. If you take human nature out of the equation, both economic philosophies are AWESOME. Humans, however, fuck everything up and need checks and balances and the push/motivation to advance the species. That and my first interactions with Libertarians were Alex Jones and Ayn Rand. There are some good ideas in there if you get past the nutjobisms.
I used to think the Communists were okay in numbers less than 100, then b_b made me read Richard Pipes. Who is exactly the kind of guy who would advise Reagan, is about as liberal as Henry Kissinger and not only concisely and completely makes the point that Marxist "Communism" has never really been tried and fails on every level, he also observes that Marxism-Leninism as practiced in the USSR and China is basically advanced kleptocracy with Marxist trappings. I think there were some serious "but on the other hand" embellishments of Communism during the Cold War and actually digging in and going chapter'n'verse on it convinced me pretty concisely that Communism doesn't work on any scale and was never intended to.