Thanks for the critics, they are very profound. I know, it is contradictory indeed to say that the state is the only possible way to protect our property and life. That’s why I never actually said that. What I suggested is that the state if limited can be a partial solution for this problem. So we have a limited state which is allowed to protect our life and property and nothing else, but we don’t lose the same right, we are allowed to protect our life and property also. I believe Rothbard or Chodorov (I am not sure) or maybe someone else said once that without the income tax socialism (and collectivism, let me append) is impossible, with the income tax it is inevitable, I am sure he is right. But how did we get there, the state has no power except to protect our life and property, how did this power let the state to impose income tax on its citizens. The other thing which leads us inevitably to collectivism is the inflation (which is also a form of tax) and inflation is impossible without fiat money. So how we get there, why do we allow to the state to impose income tax and to counterfeit “money”.
The state’s efficiency in protecting our life and property can be in a range from 0 to 100% depending on many factors. So the important thing is not to believe or to demand from the state to protect our life and property with 100% certainty, because this would be an unreal expectation, and would lead the state to act as an organization of prevention and not as an organization of protection. This would eliminate the state from the business of building roads, regulate commerce, running schools etc. Prevention requires speculation about the future, and as Mises teaches us in his great work Bureaucracy, the state is here strictly to implement the law, not to speculate and not to improvise. As a contrary today we have a state which only consideration about the law is that when they decide to do something (based on speculation and not facts – remember the Iraq war and almost everything else) and there is no existing law about that, they would make a new law so that they can say that what they do is actually according to the law.
The other important thing is that if a state is truly limited it isn’t a monopoly on force because it can’t use force except in a case when someone attacking our life and property, but as I said previously, we have the right to use force as an individual also (self defense).
I would be the happiest person if we can live in a true anarcho-capitalism with competitive private business in every area, without a state. But I’m afraid, that my logic tells me that it isn’t possible, that it is utopia. So I’m looking for the next best answer.
Consider a state as a help for every individual, a help in exactly one “business” protecting life and property. And an individual have the right to refuse help if he think he is better off without it, the state should respect this, because remember the state derives its powers from the rights of the people, and if an individual don’t have a right to impose help on other individual, how does a state come up with that power? A new question needs answer: If it isn’t mandatory (to accept the help from the state) doesn’t that mean that we can have more than one state in one particular geographic area? I have some initial answer, but I am not satisfied with it, so I need to “go back to the drawing table” 
Is this kind of limited state achievable? I believe yes.