I bring lots of gadgets in my bag. iPhone, iPad, iPod, wifi router, another smart phone, bluetooth headset, sometimes MacBook Air, and Moleskine.
I don't know why but when I polish my idea, I mean brainstorm?, I prefer hand writing/drawing.
It works better than when I start with Evernote or Keynote.
But this gadget made of paper is too fragile to roughly put into my bag with those hard devices so I made a leather cover for it. Looks nice :)