Google has acknowledged my authorship markup and attributed my Google+ profile as the author of my pages. So now my profile pic appears next to my listings in the SERPs.
At first this actually seemed to hurt clickthrough. Apparently people didn't feel that my mug shot was relevant to their searches.
So I changed my profile pic to an image that's relevant to the content of my main site, in particular to a seasonal topic that's important. I saw an immediate, significant boost in clickthrough, mostly on the SERPs that are directly relevant to the pic but also somewhat on more generic SERPs as well.
What really impressed me is that the change in profile pic took effect instantly. I changed the pic, and the SERPs changed right away - so it's pulling the pic directly from my profile.
This opens up a whole new realm of image-based clickthrough enhancement. I'll have to experiment with different images to find out what will work best for the whole site.