[It] could be argued that the favorite sin of Satan would not be vanity, as described in 'Devil's Advocate', or even unbelief in the existence of the devil, as described in 'The Usual Suspects,' but the imagining of a generic, Christless God. The very essence of the Christian faith centers on the identity of Jesus Christ as God's only begotten Son, who alone is the source of salvation and author of faith (Acts 4:12). So it stands to reason that Satan's favorite sin is the belief in a God without Jesus, because that is a god without atonement or redemption and that is what populates hell in the name of heaven.
~ Brian Godawa