I have carried for quite a while an Eagle Creek cloth briefcase/backpack item that usually contains pens and notepaper, cell phone, spare glasses, small FAK, munchies, a small hooded jacket (Patagonia Houdini-4 oz), and usually my lunch. When I am commuting on the bicycle, it slips nicely into one of my rear panniers. I find that, off the bike, I usually sling it over my shoulder on one of the pack straps. It works just fine as a day pack on short hikes - probably one of the most versatile gadgets I own. Works everywhere from the workplace to the woods.