I'm one of the more reasonable libertarians (if you can even call me one). I believe that calling taxation theft is unproductive. I think one of the big pitfalls of mainstream libertarianism is the failure to understand the definition of government.
Government can be defined in layman's terms as the practice of pointing guns at people, taking their money, and using it to do things. We want to build a society where that doesn't happen, not one where corporations and criminals, absent the "legitimate" government to control them, end up holding those guns instead.
This is our last chance to get it right... we are building the next oligarchs, the last ones... here today. Who we choose to support and the technologies we embrace are critical.