Atheism from the perspective of a theist

In my experience, true, abject atheism is hard to come by. The reason being is probably because we live in such as theistic world that fully being able to deny any God existing has some kind of logical contradiction associated with it.
This isn't always the case, but I will try to explain it as well as I can. Pascal (whom I've already written about) stated that only the truly irrational deny any existence of a God, because in this existence they are inevitably damning themselves to either non-existence after life (if they are correct), or to eternal damnation. In Pascal's mind, the rational person will either believe in a God, or, failing to have enough faith for that, will at least seek some kind of God, not being content with the idea that there is no God and not being content with not knowing (an agnostic who stopped searching for God would be irrational).
And, in fact, in the world of philosophy, when atheism became a real factor, it was represented by Nietzsche, whose denial of God was so complete that he even completely denied the ethics of believers as having any real value to them.
But we have lost that sense today. We live in a morally relativistic world where we often forget that many of the basic fundamentals we follows (those not found in the universal law that all humans follow) are the result of our Christian heritage. But Nietzsche understood this. Furthermore, he understood that a lot of these basic guidelines we follow are the only things restricting us from being utterly and completely base and selfish. He understood that all humans have the "will to power" which he hypothesized governs our lives.
So, for Nietzsche, the fear of an imaginary God was a silly one, and the inhibitions that normally prevent us from trampling everyone in order to further our own desires was a silly list of pointless rules.
However, in today's world, the atheist finds himself often following these rules. Upon questioning, I find that I rarely get a coherent response as to why we, as selfishly driven humans, would ever sacrifice anything great for little or nothing (like the martyrs for example). Of course, the promise of a glorious afterlife seems to be the basic reason for a lot of people's ethical choices. In fact, I would go so far as to say most of Christendom follows many of their principles for that reason. Likewise, many other basic components of decency are lost because of their lack of emphasis in Christendom.
However, the one thing I am most perplexed about is how someone can fully deny the existence of a god. I understand that one can not believe in God, just as someone else can. However, while God is not provable, at the same time, God is not disprovable. I can claim to feel God's presence, or have a mystical experience, or see miracles or appeal to the order of the universe and our bodies, and someone else can just as easily call my experiences psychological, the miracles to be chance events and the order to not be order, but just the result of a chaotic explosion billions of years ago. However, in these refutations, my opponent has never shown how his thoughts prove no God. After all, God could have caused the big bang, evolution, chance events that continue to happen today and could have altered my psychological state to experience His presence.
So in my thinking, it makes more sense to state that one is an agnostic. It is clearly easier to say that one does not think that there is a God because he has never seen proof enough than for someone to claim that there is no God because he has apparently come by some knowledge that clearly demonstrates that there can be no God.
And so I rest with my first statement: atheism, as atheism is irrational. However, I must also add that dogmatic belief as unquestioned adherence to an unexamined tradition is also irrational.