Independent is one thing, but Libertarian is just another party. Even if there were a real viable 3rd party, a 3 party system is still not a real choice. The point of Jesse Ventura's book Democrips and Rebloodlicans is that we need to get rid of political parties all together. Not only would people be forced to investigate each candidate, but no one would have to toe the party line either. In some countries low voter turnout renders an election invalid. So not voting (or rather a vote of no confidence as I like to think of it) can effect change.
Speaking Truth to Truthers