IMO if you're seriously considering using the pen and need to rely on script recognition, Thinkpad Tablet is hard to recommend. With current selection of pen-friendly software recognizing written text (consisting out of exactly one 1.0 product at the moment) anyway.
Windows-driven Tablet PCs, like X220, are heavier and more expensive, and won't work as long on battery, but have much larger screen, much more responsive pen (don't have to wait for a half-second between drawing something and seeing it), decent recognition and overall much better software support for inking (starting from OneNote, decent MS Office support for inking, and even Evernote). There is also upcoming Samsung 7 tablet, with promises of comparable weight and reasonable battery life, although still more expensive.
That said, if you do not need the recognition, for occasional note taking/drawing WritePad Stylus (especially with the latest Thinkpad-special tweak from the developer) and Skitch are quite usable. If you don't mind the looong delay between drawing a line and actually seeing it, can even do some painting in Autodesk Sketchbook Mobile.
