If we don't believe, and God is a fair god, he will judge us on our merits, not on whether or not we worshiped him. This is the problem which has plagued my understanding of the Christian religions. The proponents of these different cults all espouse their own superstitions as the only true religion, and all non-believers are condemned to everlasting torment. It's not sufficient to just be a believer, you must be their kind of believer.
From a non-believers perspective, then, the Trinity is just a means of explaining the contradictory natures of God. There seems to be no other means of reconciling the Old Testament God with the just and merciful version of the modern world.
I would recommend a book by Robert Heinlein called "Job: A Comedy of Justice" for a different perspective on God, Satan and religion in general. Yes, it is fiction, but there is much to think about in there.