Quote Originally Posted by Hax View Post
God is mostly used to denote the Judeo-Christian/Islamic God, as opposed to other gods.
Yet more accurately, it is capitalised when you believe in what you are capitalising . If one does not believe in the deity they are writing about, then one would normally leave out the uppercase letter. Although some will do it out of respect, if they have it.

Ideally though, we are all (Jews, Christians, Muslims) supposed to believe in one, same god, as that is how it was (we all worship the same deity). Now certain people may argue otherwise, although just as many will insist the god is shared.