My font pocket is completely full with all my fonts, so I keep my N900 in my front-left jeans pocket.

The only other thing I ever put in that pocket is a handkerchief. Once without thinking, I put the Nokia earbuds in there, and after a ten minute walk the 3.5mm plug had already scratched the screen protector.

One problem I had was that the lens cover sometimes worked its way open and drained the battery. Because of that, I now always put the phone in the pocket one way only (screen outwards, camera towards the top) and it never comes open anymore.