To take the absurdity of an omnipotent creator a bit further:
If I understand correctly, not only do most Christians believe that god is omnipotent, but that he created *everything*. This would imply that any conceivable variable that comes into play when you make a decision is a direct result of gods creation. Whether it's the chemicals in your brain, the environment surrounding you, or your soul (if you believe in such a thing), god created it. There is nothing outside the realm of gods creation that influences your decisions.
Furthermore, because of gods omnipotence, at the time he created everything he would have known exactly how his work would result in your future decisions. Your choices are a reflection of his own choices and your poor choices are a reflection of his poor design.