We here at Campy Only are great believers in the value of reflective gear for our bikes. We put in a lot of miles after dark, both training for and riding in randonneuring events, and we've found a few inexpensive items that will help make your bike more visible at night.
The first are self-adhesive reflective decals that go on your rim around each spoke. The ones we use are called "Spokees," available online from www.funreflector.com They're available in several shapes and colors, including a "stealth" black that isn't quite as reflective but blends in well with black anodized rims.
Here's a photo of a diamond-shaped Spokee on one of our bikes:
