Autodesk/SketchBook Pro
From Mobile PC Wiki
"Designed specifically for use with Tablet PC or digitized pen tablets Autodesk SketchBook Pro software delivers the industry’s best-in-class tools: fast, reactive pencils, markers and brushes; pen driven layers; background templates; a 75-brushstroke undo/redo option, and a unique pan/zoom tool. With the well-designed, streamlined user interface and fast intuitive workflow you’ll have high-quality digital sketches in a matter of minutes."
See Chad Essley's excellent comparison Artrage 2.0 / Alias Sketchbook Pro
