Every time I decide to ride in, I contemplate taking my road bike with a messenger bag, instead of my commuter with the rack, panniers, fenders and lights. I know that I can ride the roadie a good 5 mph faster, even uphill, and that it would be a fun ride. But every time I end up taking the commuter. My messenger bag is actually the pannier, with an easy conversion system, but I still don't like riding with it on my back.