There has never been a civilization that did not have a form of diety worship. Widely accepted atheism is a relatively new development in human history. Some view this as an overall win for societal progress, and others view it as a loss. In America, the arguments against religion are often along theological lines, but not enough focus is paid to what I believe to be the paramount purpose of any religion: Influencing us to act in ways that makes others' lives better here on earth. The major religions of the world, Christianity, Judasim, Islam, Buddhism and Hinduism all have sacred texts that demand certain behavior from us. Based off of my limited religious study, the religion that appears to be most concerned with our earthly behavior far more than afterlife, theology, messianic prophecies, etc. is Judaism, and specifically the first five books of Moses, also known as The Torah or the Old Testament. It is *obsessed* with ensuring that we act a certain way. I will give specific examples of this later, but I want to address Secularism and Atheism in a personal way for a moment.
I grew up with almost no religious teaching and still do not attend any religious service. The only exposure to church and the bible that I received was through occasional attendance of services in order to meet merit badge requirements for my Boy Scouts activities. I never felt connected to religion or God in any significant way, and as of yet I do not have a personal relationship with any God. I am open to the possibility that a God exists, and books like "The Science Of God" by Physicist Gerald Schroeder are certainly offering me compelling arguments in favor of the existence of a God. What is more important than whether I have faith in a God or not, is my behavior, and that is what I believe to be the primary purpose of religion. That said, I am not aware of any contribution from the secular world to this end. If there is a secular 10 commandments, I am not aware of it.
Examples of how Judasim improves our behavior:
These are just a few of the examples that have had the most profound impact on my life from Rabbi Joseph Telushkin's fantastically simple to use book "The Book of Jewish Values":
From Mishneh Torah "The Laws Of Theft", Bava Kamma 10:9
It is forbidden to purchase an item from the person who is responsible for protecting that item. For example, if someone who works at a supermarket offers to sell you dairy products at a discount, you may not buy them because there is the possibility that this person stole those goods from the supermarket. This is so important because if everyone practiced this, there would be much less theft, as the market for reselling the stolen goods would not exist.
From Deuteronomy 22:1,3
This text demands that you return lost objects. From Telushkin's book: "Jewish ethics regards keeping a lost but potentially identifiable object as a particularly serious sin, for this is not only a form of thievery but a sin for which one can never fully repent. Even if one subsequently regrets one's dishonest behavior, it is very unlikely that he will be able to find the person to whom the item belongs; therefore the finder will have no way of undoing the evil he has committed (Maimonides, Mishneh Torah, "Laws of Repentance", 4:3).
Ethics of the Fathers 6:6
If you repeat an idea that was created from someone else, you must always cite who created the idea, lest the audience believe that you created the idea. It is viewed as a form of double thievery in Jewish law: You steal the credit due to the person who first enunciated the idea, then you engage in what Jewish ethics calls "stealing the mind". You deceive your listeners into thinking that you are smarter or more knowledgeable and insightful than you really are.
So those are just a few examples from Rabbi Telushkin's book. There are 365 in all, one behavioral modification for each day of the year. I believe it is this Jewish contribution of behavior modifications that makes the largest impact for good in our world. In over 2,000 years, there has been no superior set of behavioral guidelines developed - even by non-religious thinkers during or since the enlightenment.