The difficulty with utilitarian justifications (for anything, not just taxation) is that it compartmentalizes individual actions. Why is it moral to abort Hitler but immoral to abort someone else's baby? Why is it immoral to mug a guy in a back-alley (assuming you don't really, really need that money) but it is moral to take a percentage of their hard-earned wages against their will?
Utilitarian thought obfuscates moral and ethical considerations with a certain pragmatic results-oriented thought in which a perceived end can justify any action. One useful tool to double-check utilitarian arguments for rectitude is to find the logical form of the argument being made and replace terms with functionally equivalent terms and see if the argument still matches one's intuition.
Sax and Violence is an excellent, artful, and cogent demonstration of this approach to double-checking a utilitarian argument. There are those out there who will find that both taxes and saxes match their intuition... and those people terrify me. There are those that will discover that both taxes and saxes are counter-intuitive after reading this article, as well. However, it would take an act of willful ignorance to say that one is morally justified whilst the other is not.
You can watch a video that has a reading of the text and a further exploration of the idea, but the audio quality is a little shoddy.