I fluctuate between anarchist and voluntarist. Dropping the "Y" makes it easier to pronounce while maintaining the root word "voluntary."

Agorist is another good one too. Someone who operates outside government and coercion.

I think it depends on the crowd. Everyone is surprised when I mention anarchy and they find out that I don't shoot cops throw Molotov cocktails at businesses. It makes for a good conversation starter some times.

I will also say that I think the label "libertarian" is almost useless to most. Thanks a lot Gary Johnson.