Here is a link to an article by Tim Keller about his vision for how Christians should interact with the culture around them.
Here is an excerpt: “Once in cities, Christians should be a dynamic counterculture. It is not enough for Christians to simply live as individuals in the city. They must live as a particular kind of community. Jesus told his disciples that they were “a city on a hill” that showed God’s glory to the world (Matt. 5:14-16). Christians are called to be an alternate city within every earthly city, an alternate human culture within every human culture, to show how sex, money, and power can be used in nondestructive ways.”