Here is a link to an excellent summary of recent data on American church trends. It covers the Mainline Protestants and Evangelical Protestants while mentioning Catholics and African-American churches. A big new development is the growth of non-denominational congregations.
We are not seeing the death of Christianity in America, but we are seeing remarkable changes. Culture is shifting and the religious landscape is evolving. But, instead of the funeral of a religion, at least in part we are witnessing the demise of casual and cultural Christianity. And that is not necessarily a bad thing.
Read the whole thing.