First I have to say I really appreciate your response. It seems to me you have put a lot of thought into your decisions of faith. At the heart of things I think I agree with a lot of what you say, but as a scientist, and a novice philosopher, I often steer myself away from spiritual things. On the concept of man's ability to reason... I think this is near the core of any discussion on God. We think and feel and make complex decisions, and modern science still has no good explaination as to how the brain makes this possible. But knowing what I know about neuroscience and artificial intelligence, I'm confident that one day intelligent machines can be created. If this is so, then every aspect of intelligence and consciousness can be explored and tampered with in a laboratory. Facing those realities, and seeing experimental results explaining how my neurons grow, interact, and network to create my mind... I just can't comprehend my believing in having a soul anymore. Granted, this is hypothetical, but it is within the reach of science (some claim we will be there in 20-50 years although I'd put it on the latter end of that scale). For me, the ability of the human mind to explain the natural world trumps everything.
Also, on the notion of why people may act appropriately or with "morals" in the absence of God, try reading Kant's Metaphysics of Morals... I'm not experienced enough to give you a complete rundown, but he outlines practical reasons why morality necessary and explains itself without religion.
In fact, considering the vastness of the universe. The quadrillions of galaxies, stars, planets, and the proposed existence of multiple universes coexisting allow for an almost infinite space from which life can spontaneously arise. Given such an infinite incubator, the fact that such complex and intelligent life can arise somewhere is not really so surprising.... over such a space and over an untold timeframe, one might even say it's a certainty. To me, it's not life that is devine and unexplainable, it is that infinite space, time, matter, eternity.
Thanks again for your discussion.