Dear Mknight,

You remind me of Christopher Hitchens' angry book "God is not great:  Why religion poisons everything".   The claim is often made that religion has caused more deaths than anything else.  Actually, if you look at the 20th century, you'll see that ALL the mass murderers were atheists:  Hitler, Stalin, Mao Zedong, Pol Pot - and of course the rabidly anti-religious regime in North Korea.   Yes, much truly dreadful violence has been done in the name of religion over centuries.   But let me put it to you that the history of religions is an amalgam of what the original teacher taught, and the way that HUMAN NATURE has used the umbrella of the religion to distort and pervert it.  
 
Christianity was persecuted for 300 years until Constantine legalized it in 313 and Theodosius made it the official religion of the Roman empire about 50 years later.  While illegal, it remained fairly faithful to Christ's teachings, apart from some arguments over doctrine.  When "official", it lost the plot, got into bed with the government, pursued temporal power, became a vehicle for personal power agendas, leading to violence and intrigue, the depravity of the Inquisition, selling of offices, selling of indulgences.  But this doesn't vitiate the teachings of Christ;  rather it demonstrates the truth of the innate depravity of man.   
 
I look at the world around me, even in my own, peaceful country (Australia) and I am absolutely convicted that man's natural tendency is to evil.  It is only by moral and example-based education that we gave a hope of rising above depravity.

 
I am a Christian and believe that the value of Christianity is to be found, not in "C hurchianity" - the veneration of the edifices, cultural achievements, bells and smells etc, but in understanding and acceptance of what Jesus said when he explained "my kingdom is not of this world".  He said "the kingdom of God is within you" and he called us to personal transformation and holiness of life and our relationships.   Christianity gives self-control, focus, concern for others as well as yourself, and a satisfying and constructive quality to one's life.  
 
Compare the positive impact of this REAL Christianity on people's lives with the aimless, de-cultured, nihilistic lives of the people you see in any number of (essentially post-Christian) Western cities with faces full of metal, their bodies graffiti walls, interchanges with their peers a mixture of inanities and profanities - reflecting a lack of esteem either for themselves or anyone else, a total loss of any sense of community, and a lack of direction and goals in their lives.  These are some of the worst results of our loss, as a civilization, of belief in a sacred beyond, of anything outside of and greater than ourselves, and the postmodernist, nihilist concern only with 'me-me-me', and NOW!
 
Islam spread by violence and conquest.  For a while it was conducive to spiritual introspection and intellectual inquiry, but then it closed the gates of 'ijtihad' ( independent critical thought), persecuted its contemplative, personally spiritual strand (Sufiism), and after the 18th century, descended into the fanatical cesspit of Wahhabiism.   This started in Saudi Arabia, to be increasingly exported elsewhere - and is now at war both with other strands of Islam and with the rest of the world.  As Samuel Huntington says, "Islam has bloody borders and bloody innards".    Does Islam improve the quality of life of the world?  Absolutely not.
 
Buddhism is an elaborate form of secular humanism (recognizing no "God") but it shares with the great monotheistic religions a belief (karma) that what you do in this life determines what happens to you in the next.   This produces very benign ethical conclusions about how we are to live.   It certainly can improve the quality of personal, family and community life.
 
Immanuel Kant said in The Critique of Pure Reason that there can be no proof for the existence of God - but that it is in everyone's interest to behave AS IF he exists.  In other words - we should accept the discipline of a moral law that is not just something we make up ourselves as a purely situational, relative rationalization of our self-interests.
 
Dostoyevsky, in The Brothers Karamazov, has one of the brothers (Ivan) say, in effect, If God doesn't exist, then everything is permitted.   Indeed .... and when people act as if God doesn't exist, unless they are among the small proportion of humanity that is highly educated and personally reflective (this includes some humanists), they are likely todo absolutely what they like, when they want, without regard to the consequences of their behaviour either for themselves, their families, their acquaintances and their communities.   
 
I don't excuse the abuses in the history of religion.  I merely point out that a religion which focuses on the good, the beautiful and the holy, and is internalized in yourself, in the way you relate to other people and to God, the source of goodness, holiness and beauty, is a powerful and wonderful antidote to the evil inherent in man, shown in his capacity to be callous, cruel, rapacious and self-seeking.