I'm an agnostic, but only because it is impossible to tell either way for sure whether god exists or not. But I tend to veer towards the side of the atheists because at least, from a pure scientific evidence standpoint, the evidence against the existence of god is stronger than the evidence for the existence of god.
Certainly I do not believe in the type of god espoused by most religions, that of a sentient all benevelant creator who listens to our prayers, decides whether we go to heaven or hell, or gives a fuck whether we worship him on sundays or not. I instead am open to the existence of a "God of Spinoza", not a deity per se, but something that is one with nature and the universe.
I will not deny however that Religion does and can serve a useful purpose for humanity. Perhaps a misguided purpose but it is as people's natural inclination to desire to believe in something.
Religion was used for many purposes, bring legitimacy to the monarch, manipulate and pacify the people, bring a sense of purpose to once's life, help explain things that were not yet explained by science, and as Mickey says to provide some moral compass and subsequent reward for the afterlife. All of this was man-made of course. God exists more in our brains than anything else!
I also fully except that there is nothing after we die. Instead of complaining that we don't get anything afterwards, we should instead be thankful for the little time we do have, and its all the more reason to live your life to the fullest.