There are a few applications I'd like to see.

Top of my list is -- regrettably -- a closed-source, commercial product: PhatWare's Calligrapher handwriting recognition (http://www.phatware.com/calligrapher/index.html) or even -- dare I dream? -- the whole PenOffice. Unfortunately it's a Windows-only (both desktop and WinCE) product, so...

The other one would be a port of Gournal (http://www.adebenham.com/gournal/). Or perchance Evernote (http://www.evernote.com/en/)? Again non-free I'm afraid, but at least one of the developers once told me in a mail that a Linux version was "under consideration".

In case anyone wonders about my mental sanity: I used to be a Newton geek.