The safety blanket used by anicient peoples to defend themselfs from the unknown. Later developed into a system of control. For some strange reason, people still believe in him.
Common arguments for the existance of god; "God is great, god is good, god exists, the proof is in the Bible"
Common arguments for the non-existance of god; The world, people, George Bush, physics, chemistry, biology, astronomy, all other science, phychology (its only use), common sense.