Virginia Postrel identifies in the American libertarian movement "four distinctive yet complementary traditions, two cultural and two intellectual." She clearly favors the "Hayek-Friedman" tradition:
Most of the libertarian movement's persuasive and policy triumphs have come from this non-utopian, empiricist approach.For extra credit, read it all.
Instead of the Continental quest for certainty, this second intellectual tradition is inspired by the Anglo-Scottish heritage of skeptical inquiry. It is the tradition of Smith and Hume, animated by a love not only of liberty but of the learning, prosperity, and cosmopolitan sociability made possible by a society in which ideas and goods can be freely exchanged. It looks for understanding, for facts, and for solutions to specific problems. Its distrust of grand plans and refusal to embrace the one best way—even the one best libertarian way—made it out of place in the 20th century. They make it essential for the 21st.