To attempt to clarify the whole agnostic/atheist thing (going by the actual meanings of the terms).
An atheist doesn't believe there is a God, because there can't be one. I.E. they find the entire idea of a God completely impossible. Which makes them no more right than religious people IMO.
An agnostic says it's possible that a God could exist, but since there is no proof, they assume there isn't one. Basically, Occam's razor. Generally, if someone's reasoning for not believing in God is there have seen no proof, they are an agnostic. There are subdivisons, for how likely someone thinks there is a God, from a very small chance to even odds. I forgot the terms though.
And if someone is against the idea of religon, that's being antitheistic. It has nothing to do with atheism. E.G. Unleashed.