The UI created by Microsoft is somewhat dependent on an active screen, alla Wacom. People have asked me oh-haha-your-tablet-is-now-obsolete, what with the advent of the iPad, and I just shrug them off because the iPad is quite useless for notes, as without pressure sensitivity (or for that matter, a well-established note-taking system), the thing is pretty bad with handwriting. Unlike the iPad, Tablet PCs also often are convertible; mine is, so it comes with a hardware keyboard, which makes Matlab and Mathematica much more enjoyable.
Also, there's an entire piece of software within the Office suite (OneNote) that's made for the Windows Tablet PC user. It's been around since Office 2003, but the latest version is just amazing. It's got LaTeX-like math input, math input by pen (not too good, but acceptable for basic math), video, audio, picture recording with voice recognition/OCR for the latter two, among other features which are helpful for notetaking.