nontheist - a person that never considers religion in any form.
Differs from an atheist in that an athiest's belief is in not having beliefs.
Differs from an antithiest in that there is no active rebuttal of beliefs.
Essentially someome that neither has an opinion on, nor thinks about religion at all.
My friend John is a nontheist. I have never heard him engage in any religious conversation and when asked he honestly replied he had never really thought about it.