Christians have drawn on a number of images over the years to get at the significance of Jesus' death on the cross. Unlike Christian beliefs about Jesus, the church never settled on just one picture. He satisfied God's anger. He took our place. He showed us God's love and how to obey. He defeated the evil powers that rule this age. These are all lenses through which Christians at different times have explained what Jesus did on the cross. All of them have truth to them.
But the image that I think might speak most to our current age is reconciliation. In a broken world where AIDS has left thousands of orphans in Africa, we understand the longing for a father. In an America where a child is as likely to grow up in a broken home than in one where your parents have been together your whole life, we understand alienation and distance. We understand brokenness and the need for reconciliation. Some of the images Christians have used throughout the centuries may have strong features of other times--how many of us have ever seen a sacrifice? But we "get" alienation and the need for reconciliation.
Atonement is reconciliation that takes place because of some sacrifice, some offering. God himself made the sacrifice. Jesus gave himself as the offering so that we might be reconciled to God (cf. 2 Cor. 5:18-19). The righteousness of God in Romans is God's propensity to reach out and rescue his people and, indeed, the world. In a world of profound alienation, this message still rings out as immensely good news!