I'm not so sure having a label for those who do not believe in the existence of 'god/s' is such a good idea. It is those who do believe, those who are asserting 'god/s' (whatever) existence, that place upon themselves the burden to define what that term is supposed to refer to in reality. It is only with regards to a valid concept that one can begin to systematically evaluate its correlation to reality. It is only in relation to what someone is that another can say what they are not and it is only in relation to a solid definition of what someone believes that another can say why they do not and why no one should.
The term 'atheist' has pretty much proven to be no less vague than the term it is intended to stand in opposition to. The only way out of that quagmire is to ask the believer to specify what it is they believe in and then you have something that is accessible to refutation. I doubt that any additional such terms will shed any more light on a matter which is, by virtue of its essential ambiguity, drowning in the very quagmire it created at the onset.
Is it any wonder they place their gods, beyond the clouds, out of reach, and inaccessible to those who might question its existence?