Saying that God must exist because matter and energy could not "come from nothing" (or, the alternate argument, that the universe is far to wonderful and complex to not require sentient intervention) doesn't serve to do much besides push the problem back one step. If something wonderful and complex requires a creator, it follows that that creator is at LEAST that wonderful and complex. The question, then, is who or what created God? I know, you'll say that God has always existed, however, if that can be true of God, why not of matter and energy?

Simply saying that God doesn't have to follow the rules of this Cosmos or any rules at all (consevation of matter and energy, entropy, etc) doesn't really cut it (after all, it all boils down into the argument from ignorance again.) If God can interact in our universe to the degree that you believe (ala flooding the world with far more water than could be stored in current cloud systems) then it follows that he has at least some traits in common with this universe. That is, in order to exist and interact with this universe, you need to, by definition, follow its laws.