I carry a hiking backpack for work, primarily for things when I'm goofing off (comic books, ipad, copious amounts of snacks). I try not to carry a bag when I can avoid it, so just keys, wallet and phone in my pockets when I'm with friends. When I was younger, I would use a messenger bag so that I could still carry my things in something other than a purse. This was before I had the confidence to just start buying clothes in the men's department.