Of God, egoism and relativism, which stands out most within American culture?
All of these things stand out in American culture, though they do so to different degrees in different parts of that culture. This is part of what makes American culture so diverse.
In some parts of American culture, God stands out much more clearly than in the cultures of most rich countries. Americans are very religious compared to, for example, the people of Western Europe. This stands out, for example, in the degree to which American political figures are required to profess Christian faith.
At the same time that Americans stand out for their Christianity, they are also prone to egoism. This is the view that people should act in ways that are meant to maximize their own self-interest. This stands out most clearly in American society in our attitude towards government. We want the government to do things that help us as individuals more than we want it to do things that are beneficial to society as a whole.
Finally, relativism stands out in many of the more liberal areas of the country. Many Americans feel that society has no business dictating how people live their lives. This attitude may be based to some degree on the idea that there are very few absolute rights or wrongs. We can see this attitude, for example, among those who feel that society has no right to “legislate morality” on things like gay marriage.
All of these ideas stand out in the US. If I had to pick which one stands out the most, I would have a hard time choosing between God and egoism. It seems to me that American culture stands out most for its mixture of piety and self-centeredness.