Ok - bracketing the entire God as the source of all matter, reason, goodness, etc. piece, let me speculate. This gives me the freedom of a fantasy writer, with no rules, in essence allowing me to be a god and creator, so on with it...
A world without "my" God would possibly look a bit like this:
It would be void of life, death, war, famine, joy, hatred, language, and disease. It would be a world of complete and utter peace...unchanging. It would would be free of human passions, fears, and craving. It would be eternal bliss. It would be "the sound of one hand clapping", "the mind that does not understand", "No thought, no reflection, no analysis, no cultivation, no intention."
You get the idea, if there were no God, then I envision that it would be the world of the Buddhist.