I'd add "Annotating PDFs with Xournal (or doing anything with Xournal) but I guess that it does not qualify as a "common" use.

As an old-time field biologist, I really like to carry around a notebook to sketch and scribble in. Why is it so hard to translate this idea into the digital age? (yes, Lcuk's Liqbase get it). My N800 is about the size of a spiral notebook, and infinitely more useful, but Rover looks like it was rationalized away from this idea. I think Nokia's response to this is basically "Hey, it's a phone, phones are for fat fingered people, why would you want to scribble and draw on a phone?". My only complaint about the N800/N810 was no working PIM, to which Nokia's response was "PIMs belong on phones, and this is _NOT_ a phone, you want a PIM go buy a phone". </useless-grumbling>