A previous post of mine has been superseded by an excellent article in Skeptic Magazine (vol. 13 no. 2) by Robert Lawrence Kuhn. Not only does he outline a taxonomy of different kinds of gods, but he also describes different kinds of godless material universes including illusory ones. Lucky for us the article is currently available for download [PDF link]. If that link has died, send me an e-mail and I'll send you a copy.
I'm not sure where some of my ideas would fit into his taxonomy (especially 3, 4, and 5) but his list seems exhaustive. Can you think of any other possibilities?