What would you say is the distinguishing criteria to draw the line between atheist and nihilist? I consider myself an existential nihilist and yet when I read much of the arguments made by self-labelled atheists I can't help seeing that they are intrinsically nihilistic or at the very least if followed to their logical ends, lead fundamentally to a nihilistic viewpoint. If logical, rational thinking is used then I fail to see how nihilism cannot be the conclusion.
Atheism is merely the rejection of religious beliefs, whereas nihilism goes further to saying that there is no meaning to our existence, we are just what we make ourselves to be. But how many 'atheists' fall into the latter category? If you don't believe in a creator or divine plan and you understand how our minds and emotions have evolved as chemical signals and electrical pulses then where do you fit the meaning in to this? I enjoy being alive and live as hedonistic lifestyle as possible yet I am under no illusion that this has any meaning outside of my own mind. I believe that when living memories of myself die then my existence is erased entirely, in a few billion years that anything that ever happened on Earth won’t matter, the universe will continue regardless and nothing will have any more significance than if the Earth hadn't existed at all. In trillions of years when the final stars die out and all matter is erased then time will cease to have any meaning. Oh and I can't negate the classic quote 'we have no choice but to have free will' as nor do I see that having the ability to choose one’s destiny is synonymous with a ‘meaning’.
So, what gives your life meaning and if it is indeed something only in relation to yourself then why are you an atheist?