JonMarkgo,
I believe in a God for the simple fact that man knows so little. We don't know where electromagnetism came from, how life began, we can't explain space, time, gravity, or really anything. We're good and measuring, describing, and categorizing things, manipulating them for science, but we don't understand the very basics of our existence or how they came to be. Can anyone understand death, the soul, whether there is one or not? We can conjecture but we'll never know. We'll never know why the human has this capacity to contemplate its existence.
You have to consider why the human would be put in this theatre of consciousness, of "existence", for so short a time. The chances of being placed in this state of such perfect uncertainty, in which every choice you make has to be done on pure faith, to me points to some sort of test. If there is a test, there is a Tester.
That's just my theory, could be way out in left field but its a reason to believe in God. Although your question was about religion - sorry I'm not religious, can't help you there.