I have a Kensington laptop bag and two carabiner clips on a Blackburn Mtn. rack as my pannier. Detaches in seconds and goes everywhere with me on a shoulder strap. I usually ride (~5 mi one way) in kahkis and loafers, t-shirt or wool sweater, and some sort of jacket. I bring a clean t-shirt and dress shirt with me and do a quick rinse-n-change when I get to school (I"m a CC student) or work (as a waiter in a nice place), although the restaurant provides clean uniform shirts. Add a small hairbrush, a can of Axe body spray, and some goo for my hair-all easily stashed.