Atheism is an interesting and challenging philosophy that doesn't offer much in the way of comforts that theism does. I know what's going to happen to me when I die, because I've seen what happens to others. I know that I am able to make actions and there will be a catalogue of reactions to it. I don't know a LOAD of other things, so I spend my life looking for provable answers to the problems I face, both in the physical realm and philosophically. I don't believe there is no God or gods because I can't prove it. Similarly I don't know that there is a God or gods because I can't prove that either. I would suggest coming to your own conclusion on religion and debating them with people in a way that furthers your understanding of the world, rather than creating aggressive stand offs so that you can entrench yourself further in what you have decided because you feel you have to defend it from others. Defending an idea from others doesn't add to it's validity, but it does make it harder to understand the possibility that you might be wrong. We all might be wrong. We won't know until we find out. Either way, as the advert says "There probably isn't a God so you might as well enjoy your life".