personally, i think that there should only be one religion that goes something like this:
if you're a good person, the world around you will become a better place. the better you are the better the world will be. if you lie, cheats and steal, the world will become a worse place. the worse you are, the worse the world will be.
as far as i can tell, all the other stories (that may or may not be true) create conflict between people. while these stories can re-enforce the rules, they create more trouble than they are worth, and should be left out of religion.
this is all IMO, and i'll admit that i don't know/think very much about religion.