One issue that really separates atheists from the faithful is the idea that the individual can survive death by treading the path of religious devotion.  I take the position that this belief is extremely dangerous in an era where weapons of mass destruction are becoming easy to manufacture and distribute.  Why is the idea so dangerous?  Because some people will do anything--undergo any hardship and commit any atrocity--to better their chances for a reward in the afterlife.  In most people, the idea is harmless, or it results in harm to relatively few people.  In some, it can have catastrophic consequences.

What are the advantages of belief in survival of death?  We fear death more than anything else, so this idea is powerfully attractive.  When does the belief  become malignant?  That is when the believer thinks that his or her reward will be greatest by carrying out the wishes of an angry deity.  I am, of course, thinking most about islamic jihadists who commit suicide (almost daily now) in order to fulfill God's order to kill infidels.  We have a similar mentality among Christians who long for (and may even work for) the destruction of Armageddon so that Rapture will finally come.  

The greatest threat to society today is posed by those who fearlessly commit senseless acts of terrorism in the belief that they will survive death and gain a heavenly reward for their deeds.