http://en.wikipedia.org/wiki/Tax_protester_arguments
http://en.wikipedia.org/wiki/Al_Capone
http://en.wikipedia.org/wiki/Tax_avoidance_and_tax_evasion
I used to have a friend who was a Libertarian, he used to make much of the fact that at the beginning of the tax booklet you get in the mail, there is a phrase that goes something like this: "millions of Americans voluntarily pay their taxes each year". He stressed the 'voluntary' part, saying it was not required. This same guy used to give me 'Social Insecurity' cards, printed to look like the real thing, but actually a protest about the sorry state of the social security system, which I liked and kept a few of. You can say what you like, disagree with how the money is spent, or whatever...freedom of speech is in the constitution, but if you don't pay your taxes, expect to end up in court.
Of course if you're rich, you can pay a flock of CPAs to do your taxes for you, and find every loophole in the book. That's perfectly legal, even though I think it's a crock. Which is why I'm a proponent of a flat tax system, make it so the average person can actually do their own taxes, and the rich have no loopholes. Put the lawyers out of business.