Luckily, here in Ypsi, we have a good Bike store.

They carry everything I need. But I think, as a commuter, a large selection of accessories. Messenger bags, backpacks, racks, panniers, frame pumps. tires built for commuting. Multi-tools, Tubes, etc etc etc

But its more than just parts, It's the service. Someone who knows the area, and can recommend what is best for that area.