To me, atheism is different than not having a religion. Atheism itself is like a religion in that it is a firm belief that something does not exist. I know the word atheism itself means lack of theology but an atheist still holds the belief that nothing exists. I'm more agnostic than atheist, in that I don't really know nor do I really care what does and doesn't exist.
We're all here on Earth right now. Imo, that's the only thing that matters.