Taxation is theft.  It really is as simple as that.  What would you call it when someone takes your money (your possession) away from you by threat of force when you do not want to give it to them?  Is any program or agency of the government important enough to kill for?  No!  If you don't pay the "tax" that is demanded of you, the government WILL kill you.  Maybe not right away, but at some point, if you do not submit to the escalation of force by government, you will be murdered for your money.  That is not right.

Do I have a right to my own life? What is "life" except the time you are alive? I have traded a significant portion of my life for money in order to trade the money for some other things I lack the knowledge, skill, or inclination to do personally. Does my life, expressed through my money, belong to me? If it doesn't, then your taxes would be alright. If it does, then if someone takes it from me against my will, it doesn't matter to me whether it is a government agency or a mugger in a dark alley. Now, you may argue that the money is being spent on "good" things. OK. Maybe the mugger will use my money to feed his children, or will donate it all to a charity. Perhaps he will even purchase a gift for me with the money; something I won't buy for myself. Does that excuse his actions? What if I refuse to cooperate with the mugger? He will probably use greater force unless I am able to effectively fight him off. Just like government.  If you refuse to comply with them, and keep refusing at each step of the "process", the government will reach a point where it will kill you for your money. Either when they try to confiscate your property, or when they come to forcibly arrest you, if you fight back, you will be killed. What government program is worth killing people over? Innocent people.  People who only wish to keep that which belongs to them.

The things and programs that are financed with your stolen money could be done cheaper and better by private companies or individuals.  "User fees" could be charged for some things.  If government still wants to be involved, let them end their monopoly and compete in the free market.  Private roads could be maintained through tolls or paid for by the businesses they serve.  Poor families could be helped by charities that do not take away your dignity like government "welfare" programs do.  "National defense" would be better served by the Constitutional militia than by the military pawns that are sacrificed for bogus "causes" in distant lands now. 

Many, if not most, things government currently wastes your money on would not need to be replaced by anyone in a free society.  Stupid things like the DMV, BATFE, the Pentagon's "black budget", and Congressional salaries.