As a scientist, I find it depressing that people would engage in this kind of behavior. But on the issue, I just watched this MIT "debate" about the impact of this incident:
One thing I specifically remember is that one of the panel members (and member of the IPCC) concluded that the attempt by Mann et al. to bury conflicting studies was not successful, as some of those very papers were discussed and cited in the IPCC reports.
It seems to have been included with a dismissive editorial comment ("Michaels says X, but he's wrong"), which was not supported by any literature, and which the authors were not given the chance to respond to before publication. Just mentioning that "it was included" is a bit misleading.
I believe if you reduce the argument to one or two specific papers you can easily see that they get out.
More distressing is the overall pattern of behavior, where editorial boards are rigged and scientists just "give up" working in this field. No amount of good papers getting through is going to fix that, unfortunately.
http://mitworld.mit.edu/video/730
One thing I specifically remember is that one of the panel members (and member of the IPCC) concluded that the attempt by Mann et al. to bury conflicting studies was not successful, as some of those very papers were discussed and cited in the IPCC reports.