When I'm wearing a suit, I generally take my Longchamp soft-sided case in black leather to work. If I'm wearing jeans, it's usually my trusty black Jansport pack. Lately, I've been considering messenger bags and attache cases, but the contrarian in me resists, as so many guys are carrying them (especially messenger bags). What are you guys carrying with you to work/school? Do you carry certain bags when you're dressed a certain way?