Just came across a short blog post by Andrew Brown at the Guardian that articulates, quite brilliantly, some of the themes I've been working on here.
Money quotes (emphasis mine):
Religion can't really be about doctrine and heresy... because these concepts don't make sense in pre-literate cultures.
[M]aybe it would be better to say that religion is a myth that you can dance to. This is useful because it suggests that atheism is not a religion as you can't dance to it. There's no shortage of atheist myths – in the sense of historically incorrect statements which are believed for their moral value and because it's thought that society will fall apart if they're abandoned. The comments here are full of them. But they are no longer danceable.
There aren't any overwhelming and inspiring collective atheist rituals. I don't mean that these can't exist.... But they don't exist today.
If I'm right, then liberal, individualistic atheism is impossible as an organising principle of society because any doctrine that actually works to hold society together is indistinguishable from a religion. It needs its rituals and it needs its myths. A philosophy will grow around it in due course.
Go read the whole thing here.