Anyone concerned about the sad state of Christianity in America would do well to read (re-read, archive, and read weekly) one of Seth Godin's recent posts: Thinking About This War\. Go ahead, read it, I'll wait.
What does this have to do with the Church? Everything. The current failure of Christianity in the United States has to do more with marketing than we may ever have previously imagined. Marketing is basically telling a story. Christianity is telling the wrong story.
The current story is about a rampant individualistic existence that does not care for anything outside of oneself, except possibly a deistic god. It is about giving up things that seem like God created them (tobacco, alcohol, dancing, fun) so that you can live it up in heaven some day (doing what, exactly, is not mentioned much--what is mentioned is what happens if you do live like a human...hellfire). The pietistic instinct in dualistic Christianity eventually forces it this way or towards an antinomian "social gospel", like what happened to the mainstream churches in the 19th and 20th centuries.
To folks we live in the world of materialism and "wealth-as-happiness", the constricting story of Christianity doesn't make much sense. It is easy to shrug off, especially since the loudest voices have been the worst representatives (it is hard to maintain that homosexuality is wrong while engaging in homosexual affairs, as the non-Christian world pointed out to the evangelical community recently).
This is not to say that the story Christianity must tell is the one that the world wants to hear. That is just another death-affirming road, just like pietism. Instead, it is time that the true story of the gospel is told: God created the world, evil has infected it, Jesus has come to cure the infection through his work and his people, and God is calling everyone to join in the rebuilding effort. Instead of denying Creation, this view puts it in its proper place. Something is wrong; there are broken families, alcoholism, inner-city and suburban violence, the loss of millions of tons of topsoil every year, and slavery to name a few things. The gospel does not affirm these things, but instead calls them what they are: abberations from what God intended and commands. However, the gospel does not go so far in the other direction to deny Creation by saying that alcohol or aggression or farming or work are wrong. Instead, working within the limits of creatureliness, we in the Church, through the work of Jesus in history and in our lives, try to reestablish God's good purpose in his good Creation. We change structures of injustice so that God's intention for man and for the rest of the world might stand. It does require us to tell a hard story that conflicts with many other stories. But the story is ultimately life-affirming and the Church needs to stand in the role of priest and intercede for the world.