"You benefit from government services, so..."
"I like to pay taxes. With them I buy civilization." - Oliver Wendell Holmes
The above quote encapsulates the answer with which liberty activists are often met. We are reminded of how much we owe to our various levels of government. Have you been recently accosted? Of course not, because your tax dollars pay for the police. Did you take the road to get here? The government built our road system. You should pay your taxes because you benefit from the government's services.
The implication is that we are ungrateful... er, ingrates, but it's a silly argument. The position is akin to nothing so much as that taken by the homeless man who sweeps a cloth over your car window and sticks out his hand expectedly (then proceeds to break your wipers if you renege on paying for the service you didn't request).
Benefiting in no way obliges the beneficiary unless that beneficiary has asked. I don't owe the government anything.
Neither do you.