This older post on a libertarian Yahoo! Group is a must-read:
Also make sure to read Richard Garner’s excellent Response To The Anarchist FAQ.
Finished? Good. Because now it's time for my two cents.
Rothbardian anarcho-capitalism, influenced by Lysander Spooner and Benjamin Tucker, retains most of their spirit but omits their silly ideas and errors (such as the labor theory of value, which nobody believes in anymore). In my opinion, it is simply a modernized form of market anarchism with the crap cut out. Does that put it outside of historical/classical anarchism a bit? Yes. Who cares?
Tucker is one of my all-time favorite anarchists. His article Relation of the State to the Individual is one of the best introductions to anarchism out there. And it's one that Rothbardian market anarchists will find little to disagree with--except for his crackpot ideas about "usury," which are thankfully kept to a minimum this time around.