Products I've used for commuting and have come to prefer:

1. Honjo/Berthoud fenders. They are expensive, but they really work. I haven't yet found a more affordable fender that keeps the water off my feet like a long Honjo.

2. Brooks saddles.

3. Panaracer tires, preferably the Pasela. There are plenty of good tires out there, but these are by far the best I've tried.

4. Surly Nice Racks. They may be heavier than some people prefer, but darn it, they can do just about anything. Want to haul 60 pounds of groceries after work? No problem. The front rack is probably the best product I've bought for my commuter.

5. Kool Stop salmon-colored brake pads. I have two bikes with V-brakes, and thanks to these pads they feel stronger than the Avid Juicy 7s on my DMR. Also, they're almost always QUIET.