you cant really judge an all atheist society by the kinds of atheists we have in america today. these are typically smart critical thinkers and well behaved people because they are so rare and somewhat disadvantaged socially. if they become the norm, all the normal human behaviors then get channeled through a lack of belief which in some ways may be different, but in other ways may be the same.
right now, most inmates and racists are religious, but in an atheist society, obviously that would change. i think there would be a reduction in racism and crime, but it wont go away completely because you can find "rational" reasons to be a racist or a criminal.
you can look at sam harris' attitudes toward muslims for an example of how we can still end up with tribal/racial/fascist/intolerant attitudes in an atheist dominated society. not to say he is a racist or anything, but in his philosophical pursuit for solutions to terrorism, he has openly discussed some pretty horrific things (like nuking muslims). the journey to settling group hostilities may be different, but it wont mean much if the results still lead to violence, suspicion, and oppression.
we would even see a continuing misogyny as the last few years have shown that some women feel atheist conventions are hostile to women, and even unsafe. ultimately, men are going to look for excuses to objectify women in even the most inappropriate settings, and many of them probably dont even think women can be "real" geeks, nerds, or whatever.
i still think it could produce a net positive for society since we would channel our money and resources toward things that are practical and we wouldnt let superstitions keep us from doing smart things like teaching real sex ed, and we might be less inclined to want to punish people and focus more on rights and rehabilitation (see the chart on torture attitudes) but ultimately, the scarcity of resources and human evolution will demand some degree of conflict, so there will never be utopia.