I'm frequently using staff paper to outline pieces I'm working on and jot musical ideas, particularly pieces where I'm using non-standard notation for slapping, etc. There's something about writing out music by hand when brainstorming or transcribing that I find satisfying and liberating from working on a computer. (I use Finale; I tried Sibelluius but found it to be a bit more of a life-style choice.)
There's lots of staff paper available online for download. I typically use this site which has lots of different set-ups. However, all these formats are for 8.5 x 11. A few weeks back, a friend gave me some paper that was almost 11 x 17 and it was great to work with. I loved being able to have a gig space to make notes and work out ideas.
On that note, here's a new site I recently found. It allows you to choose the paper size, number of staves, color and line weight.