Heh! That question about atheism and spirituality has me glued to my seat!
I'm intensely "spiritual" in my own world view and experience. But I'm not a theist, either.
I don't call myself an atheist, however, since it seems to me that taking any sort of position within theology, for or against, is just more theism, which I don't have any need of. (Or want of) Not only do I not know whether there is any sort of God or gods, I simply don't care either way. So what?! Why even think about it? I mean, this life has got to be enough, since it's right here, always, just as it is. Why does this life demand another? What about this life requires an afterlife, an immortal soul, etc.?
"Spirituality," for me, is mainly about feeling and being related with all beings..., you know, the ones we can see and interact with. Not the invisible ones claimed to exist in other dimentions or worlds. It is about ethics, compassion, generosity, kindness..., not about figments of mere imagination.
I have nothing against atheists. I just prefer to call myself a non-theist. I don't oppose theists so much as find their world strange, distant, curious, unfamiliar....
And this from a mystic -- albeit a natualistic one. Mystical experience can be intensely naturalistic, you know! It's about feeling integrated with all life, rather than separated from it, egoistically.