Panniers, panniers, panniers.

I built a new road bike two weeks ago, and have ridden it on my short commute to work since then. I'm carrying stuff in a good messenger bag when I'm on that bike.

I took my short-hop commuter today to the same neighborhood with a pannier on its rack. Man, it sure reminded me how nice it is to have nothing on my back.

If you're worried about speed, work on the engine.