I think where you guys would differ from me is that--consistent with a view of the intellect as a product of Darwinian processes (here comes the the crucial point)--the concepts we possess must derive their content and context from our experiences. Inferences that go beyond our senses have, throughout history, especially before the immensely accurate and helpful guidance of a more fundamental understanding of nature, generally been proven wrong. Self-delusion and irrationality are innate to us bipeds. So, when you speak about using logic to establish any kind of conception about God proper, I feel that you've not simply jumped the gun, but taken a quantum leap... in the wrong direction. If nature is as mysterious and incomprehensible as modern science has revealed it to be, what business have we defining something like God? However, I do sense that self-delusion and irrationality can entail personal benefit, and that's why the believers I can relate to are the mystics and not the philosophers; it's not the specific ideas that a mystic invokes to convey his or her interpretation of a transcendent experience but the sense they capture. But I don't make any mistakes about it: truth has the greatest potential and probably most often proves more advantageous than error, even if it requires that in exchange we surrender our comforts and are willing to modify our values.
He who loves God cannot endeavour that God should love him in return - Baruch Spinoza