I'm a LaVeyan Satanist. Basically without getting into a big drawn out discussion rife with "Satan Worship" misconceptions, we are Atheists and do not believe in either God or Satan as deities. They do not exist to us. So why the "Satanist" label? Satan is an anthropomorphic symbol for the self. The very word translates in Hebrew as "adversary", and since we are averse to all other religious dogma it is fitting. We see ourselves as our own God of sorts. It really is nothing more than Atheism with a life philosophy.