While I share gsheryl's frustration with those who seem to want to "cash in" on Jesus - I have to remind myself and others that this has always been the case: remember Simon the Magician?
There was an interesting article in Time Magazine, 12 March 2007, p. 56: "Rewriting the Gospels" by David Van Biema, that addresses the issue. It's not "just" Christianity that is falling victim to this trend, but all of history.
Instead of taking the time to develop a reputation, this generation of "historians" publishes as quickly and sensationally as possible in order to develop a reputation. They no longer write for the respect of their peers, but for the popular audience - which isn't equipped to evaluate.
I think that the university system, which promotes a "publish or perish" attitude, is as much to blame as anyone.
Our response is more important than ever. We definitely need the research that someone has suggested to Prof. Bock (I wish I had the expertise to help!) but we also need to educate Christians with the truth. Another Time Magazine article said that only 44% of evangelical teens could identify a quote as coming from the Sermon on the Mount!
We also need to educate Christians in the skills needed to effectively defend the faith. Not only do we need to know the truth, but we need to learn how to more effectively communicate it both one-to-one and in the media.
Thirdly, we need to remember that WE need to be doing this - not leaving it to Prof. Bock, our pastors, and/or other "professionals."