My thoughts on God (or maybe, more accurately, God of religion) are fleshed out in my Losing Eternity blog post. One thing I haven't mentioned there is the idea that what we call "God" might actually be the one running the simulation we all exist in. The Master Programmer. He/She/It might have tweaked a variable here or there through history in such a way as to alter people's understanding of reality to such a great degree that whole religions were formed around those experiences. Or... it could all just be some stories we created because our little primitive brains like to make meaning out of things, even if no meaning exists there.