I have heard many times that without the government to protect us, we'd all be at the mercy of those evil corporations. I disagree. I think on the whole, governments are capable of inflicting much more harm than any corporation. I don't like everything Wal-Mart or Microsoft does, but at least I am not forced to support their activities the way I am forced to support the government's activities through taxes.
Besides, the US government is heavily influenced by corporations anyway. Do you really expect politicians to create laws that are unfavorable to the people that got them elected?
Most corporations pay no income taxes, but they do have access to public money to carry out their schemes because of the government. if you really wanted to throw a wrench in their plans, the best way to do that would be to take away their muscle.
Corporations can be cruel and greedy, but they are mostly interested in making money. A corporation wouldn't set off nuclear bombs to intimidate people in other countries. They'd probably set them off if they could make money from it (charge admission to watch- nuclear carnival?). They'll throw poison in a river if it's cheaper than paying the fine or disposing of it properly, but they wouldn't spray poison to kill other people's crops or dump thousands of tons of chemical weapons in the sea.
A government is force- prisons, police, soldiers. The government doesn't protect anyone's freedom. If anything, the single greatest threat to a person's freedom is whatever government holds sway where that person lives.
I agree that there will probably always be a government of some kind around and that there are a handful of legitimate functions of a government. The presence of police for example probably deters some crime (although it would be difficult to do a cost-benefit analysis to find the ideal amount). However, most of what the government does, in my opinion, is stupid and/or unethical.
If you want to help homeless people, pay for someone's education, contribute to scientific research, or whatever, you're better off using your own time and resources to accomplish that goal than handing money over to the government and hoping they do what you want.
I can't avoid hypocrisy in this. After all, here I am in the Peace Corps benefiting from a government program. I like Peace Corps a lot and I'm glad it's around, but if it wasn't, it would not stop me from pursuing my goals. I found an opportunity that seemed like a good fit for me so I took it, which as far as I can tell is what everyone else on Earth does.