I haven't had much drawing time lately, but the Autodesk Sketchbook 2009 deal fell in my lap (apparently they're bundling it with new units - you can download it for old ones given a serial number.) Pretty nice implementation of "pencil", and good use of pie-menus for selecting obvious things. Very much a "teaser" version, though:
That said, it did get me back into drawing (though I'll probably get back to using Scribbles, at my skill level Sketchbook Pro isn't really tempting, and the limitations of the downloaded version have already wasted my time after only two drawings.) I'm starting to consider picking up an old HP TC1100 (under-$400 "obsolete" tablet) to have something I'll carry around, though...