Slate has an article about the question of whether or not religion makes you nice and atheism makes you mean. They start out by noting the appallingly negative perception of atheists that most Americans have.
Then they point to research that indicates that when people are primed with "spiritual" words, they tend to be more altruistic in a money-giving task. However, a similar effect is found when people are subjected to posters with big eyes on them. The implication? That words related to god remind people that god is watching.
Then the article talks about a book by Phil Zuckerman:
It's about the Danes and Swedes, two societies that are extremely non-religious. Guess what? They don't murder and rape each other nearly as often as Americans do. They also have fewer suicides, abortions, and teen pregnancy.
What's going on here? Well, we've got a lot of complex social variables swirling around here, so causality is very difficult to pin down. But the situation is certainly not a case of atheism destroying a society and making everyone into amoral psychopaths. The key component here is probably freedom. When people are given the ability to choose their belief system, rather than have it imposed upon them, atheists are not the evil minions of a Stalinist regime, but innocuous, hardworking people like the Danes and Swedes.
Still, I doubt many Americans will read a book like this or be swayed anytime soon by such arguments. Race and gender relations may be taking strides forward in this country, and even the rights of homosexuals, despite recent setbacks. But atheists are still overwhelmingly reviled in this country.
We've got a long way to go.