"What's left, when God is gone?" is greeted by a puzzled look and "What exactly is >missing?"

I think that this is a very important question to ask, and to really seek answers on, if this discussion is to advance any. Obviously, there are believers of all stripes who are in some sense getting a reward for their beliefs, be it socially rewarding for the culture or subculture they are in, psychologically rewarding by allowing them to be more hopeful about the future, etc. Saying their metaphysical beliefs are unlikely doesn't get at the heart of what their belief is based on, in my opinion. As has been pointed out, they don't have a robust logical structure to their beliefs to start with. So, what's "missing" from the rationalist worldview in the eyes of a believer in the supernatural is not necessarily the gods, fairies, etc., as much as the sense of safety, community, what have you, that their particular faith grants them. So, in addition to EY's equation, I'd like to suggest that atheism != anti-community or anti-loyalty or anti-love, though in the current political structures and fights we're having in the US, it almost definitely does equal anti-religion (see the teaching evolution in schools and the gay marriage debates). Untheism, by disregarding the supernatural, can still claim a lot from the territory that supernaturalists refer to as "spiritual".