Personally, I liked his 'take' on American history. He took the theories of the Austrian school of economics and wrote an entire story of the American experience as a permanent alternative to the governments story.
Rothbard is guilty as charged, however, I am sure you are aware that he did not just theorize he focused on pragmatic solutions like creating the Cato Institute, which many modern day conservatives are at least familiar with. I also point out to his practical application for supporting immigration restrictions to prevent the welfare state from recruiting more clients...that was a sharp break from the modern day, left-leaning Libertarian Party.
Lastly, his efforts to revive the Old Right in the 1990s has created an entire intellectual movement that stands opposite the DC establishment. Link below, to Tom Fleming's tribute:
http://www.chroniclesmagazine.org/Chronicles/December2000/1200Fleming.htmI am sure you are aware that he did not just theorize he focused on pragmatic solutions Yep, and he went into extraordinary detail. ...A very original thinker. I may disagree with him on (more than) a few issues, but I respect him greatly. I've wanted to check out his multi-volume set on American history for quite some time now, but have never gotten around to it.