okay, guys, I'm tired of using my jansport school backpack when I go biking. I look like a newbie having a school backpack strapped to me. but the real reason is that this backpack makes my back sweat, is awkward, and sways with too much stuff inside. can anyone of you profs recommend a good hydro/cargo pack? sometimes I ride my bike to work and have to bring clothes to change, so I need a cargo space to fit a pair of pants and a buttoned shirt. I don't want a huge pack, but one that is slim, flat-looking, and offers enough cargo space for some stuff. I'm think that maybe the camelbak MULE because it doesn't lok big and bulky and the cargo space seems sufficient for work commutes and long bike rides. any suggestions, guys?