Here's is a
link to an excellent article by Phil Johnson (a message delivered at a Shepherd's Conference back in 2005) where he points to the effects of evangelicalism's fascination with the latest "church fads" and how this has left the church woefully equipped to deal with attacks against the faith (e.g., justification controversies, the emergent church, etc.). He directs us to the power of the preaching of God's word.
It's a lengthy article, but well worth the read. I blog about it
here.