Way late response to this question, but here goes...
The majority of my photoshop time for most images goes into curves adjustment for color correction to get the colors looking right. Then, depending on the image, it gets contrasted up or saturated a bit, but that varies from shot to shot.
As for actual touch-ups, I go by the "unless requested otherwise, at most touch up things that are the product of a bad day, if anything at all", so I'll try and cut out flyaways in a wig, lint on a costume, reduce under-eye shadows, maybe a little red skin spot if necessary. It depends on the shoot and the look people are going for, really. My most common touch-up is lightening up under the eyes a bit, since we're all usually running around half asleep at cons.
I'm not sure about this one, as it was done by a photographer friend of ours rather than us, but for the most part, all we do when editing our pictures is tinker with the Curves and maybe remove distractions (awkward items in the backgrounds, branches hanging into the frames, stuff like that.) We're very low-photoshop.