[Fighting Banana Slug]

The quote is too long to repeat, but Chill, I think you are bringing up a common confusion between "belief" system and "faith". For your definition of belief system, every individual has a belief system, and so far as that goes, why even argue about it. What athiests tend to hear, is that athiesm is a belief system in the sense, in that they "believe" there is no god, as if taken on faith, as there is now way to prove the non-existence of anything. This is not an accurate statement, however, as I think it is more proper to say that an athiest does not accept a god without any evidence of same, in the same way he or she doesn't accept unicorns. If compelling evidence is asserted for the existence of god, then an athiest should be more than willing to accept, as it fits within his or her views. You might suggest that this is more of an agnostic view, but that is a problem as well, as there is a connotation with that view that those people are more "fence sitters" who think it is more of a 50/50 proposition that god exists, whereas athiests would likely argue that it is way more likely a god doesn't exist, based on our understanding of the universe, than not. Never a 100% certainty that god does not exist.

Edit: I see Troutman has linked to a similar issue above, and it is far more eloquent than I can come up with.