Bart Ehrman and Richard Bauckham recently discussed the gospels on Justin Brierley's Unbelievable? radio program. The first part has been posted, and the second should be available later this week. Neither scholar holds a traditional view of the gospels, but Bauckham is much closer to a traditional perspective.
Since Ehrman repeats many of the errors he put forward in his exchange with Tim McGrew last year, I'll point readers to my review of that discussion. Ehrman keeps asking for external evidence for the traditional gospel authorship attributions prior to Irenaeus, even though Ireneaus himself cited pre-Irenaean sources. See the examples cited in my response to the Ehrman/McGrew exchange. We also have evidence for pre-Irenaean testimony outside of Irenaeus, which I also cited in that previous post. I discussed the sources in the comments section of a thread at another blog here. Go to that page and use the Ctrl F feature on your keyboard to search for my last name. See here regarding Polycarp's likely role as a witness to gospel authorship prior to Irenaeus.
Even if we didn't have such pre-Irenaean sources, Ehrman's hypothesis provides a terrible explanation for why Irenaeus' gospel authorship attributions were so widely accepted in the late second and early third centuries (Theophilus of Antioch, Clement of Alexandria, the Muratorian Canon, Tertullian, etc.). The widespread acceptance of Irenaeus' attributions makes more sense if the attributions originated much earlier than Irenaeus.
Regarding the dating of the gospels, see here for an explanation of why Ehrman and Bauckham are both likely wrong in dating Mark to the closing years of the sixties or later. Most likely, Mark was written in the early sixties at the latest.
And here's some of my argumentation that both Ehrman and Bauckham are wrong about Matthew's authorship.
On Bauckham's hypothesis that a John other than the son of Zebedee wrote the fourth gospel, see here. You can search our archives for other posts I've written about that alleged other John and other speculations about the authorship of the fourth gospel (that Lazarus is the beloved disciple, etc.).
Ehrman makes too many inaccurate claims for me to interact with all of them here. I'll just make a few more points.
Ehrman's comments on whether somebody like Mark would have written in Greek are unconvincing. As Bauckham noted during the program, not only do we not have many Greek documents from Jews writing in that timeframe, but we also don't have many in other languages. And the issue isn't what the average Jew would have known or done. Anybody writing a document like a gospel, especially if he was a close disciple of an apostle, like Mark would have been, wouldn't be the average Jew. He would have been well outside the average, and the early Christians would have been looking for such people to undertake tasks like writing a gospel. You don't expect the average person to do that, much as we today don't expect the average Russian to write a biography of a Russian political leader, the average Catholic to write a biography of the Pope, etc.
Ehrman tells us that there's no reason to expect people to have seen a need to distinguish among multiple gospels (such as by naming the gospels according to their authors) at the time when Luke was written. But he also wants us to believe that Luke used Mark as a source, something he also says Matthew did. But if Mark was known and used so widely, and Luke had so much reason to expect at least some of his readers to be familiar with Mark, why should we think there wasn't any perception of a need at the time to distinguish one gospel from another by the titles applied to them? It seems that Ehrman is trying to have it both ways. He wants Mark to be popular, influential, and known and significantly respected by people like the authors of Matthew and Luke, yet he doesn't want to acknowledge the implications of such facts in other contexts.
Ehrman claims that the gospels of Mark and Luke couldn't have been attributed to Peter and Paul, since people knew that Peter and Paul hadn't written gospels. But, then, why was it thought that gospels could be attributed to Matthew and John (especially John, who was among the most prominent apostles)? And if people knew so much about the history of the apostles, what they did and didn't write, etc., so that false attributions couldn't have been made to Peter and Paul, then why were the allegedly false attributions to Matthew, Mark, Luke, and John so successful?
Update On 4/13/16: Here's something I've written about Ehrman's comments on Irenaeus.
Update On 4/14/16: Here's something I've written about Ehrman's comments on Papias and Justin Martyr.
Update On 4/17/16: Here's my review of the second program featuring Ehrman and Bauckham.