I just unified all my blog posts from the past half year about the Surface and the Mobile Studio under a new tag: “Magic Sketchbook”.
For me, a Magic Sketchbook is a device that does pretty much one thing: run Adobe Illustrator in a package not much bigger or heavier than a hardbound 9×12″ sketchbook, with the ease and fluidity of being at the computer with one hand on the stylus and the other on the keyboard hitting the forty or fifty hotkeys I’ve grown used to. It can do other things, it’s a general-purpose computer, but the only software I want to run on it is Illustrator, so as to eliminate the myriad distractions of the net, Twitter, IM, email, and whatever else.
I have not assembled a system that fills all of these criteria, but I think I can live with my current compromise of a (heavy, slightly-too-large, kickstand-lacking) 13″ Mobile Studio plus a Twiddler3 chording keyboard and a wire stand taped to the back. Looking at my braindumps along the way to this may help you make some decisions about what your magic sketchbook will be, if you have about $2k to spare.