I thought Natalie Angier's piece on the evolutionary theory behind modern taxation was a lot of fun but not really convincing:

It turns out that giving up a portion of one's income for the sake of the tribe is such a ubiquitous feature of the human race that some researchers see it as crucial to our species' success. Without ritualized taxation, there would be precious little hominid representation.

I'm a fan of Robert Trivers essays on reciprocal altruism and I could imagine a good explanation for taxes based on that kind of iterated game theory: A small group of players would each sacrifice some portion of their resources in exchange for some expected future benefit from the other members. Cheaters would be remembered and excluded from the group in later iterations of the game, which would enforce some level of compliance. And the pooled resources would benefit the group, or help smooth over difficult patches for individual members.

But the problem is that the Trivers-style argument, as I understand it, only holds in small groups. The larger the group, the smaller the benefits of reciprocation, and the smaller the chances of being caught and excluded if you fail to reciprocate.

So the fact that most people pay their taxes might be some evolutionary holdover from premodern societies. But, fundamentally, I don't think people are paying taxes out of altruism or the expectation of future altruism. They're paying taxes because because of another development: an institution with a monopoly on the legitimate use of force.