"Technically atheists just lack a belief in god, they don't necessarily believe in the non-existence of god." Qoute from a debate here.
The trouble is that atheist don't just use this meaning, they act upon it. They attack God and religion, making atheism a religion. They don't lack a belief, they just have a different one.
I am inclined to think that imagining an afterlife in one sort or another can be a great source of hope. On the other hand I think people who really do think that they are in essence immortal can't be trusted to hold life as sacred.
Arguments for and against God's existence. I'd like the negative position to take on an equal burden of proof and provide arguments against God's existence, e.g. the problem of suffering, divine hiddenness, etc.