Today I downloaded and installed Autodesk's Sketchbook Pro through the student deal as a uni student and it is remarkably lovely to use on the Cintiq tablet. I know I keep ranting about it, but it is just lovely.
Anyhow, I did a few quick tests then decided to see what would spill onto the digital page by way of a helmet. The pencil tool has a great feel straight out of the box and the interface is cute without needing any real config at all. Here is the pencil sketch and a quick colour job using the airbrush and a few layers - lotsa fun.