[ 8/20/12 edit: Model is now available in gold plated glossy again after review from Shapeways staff, given the history of the part. You should be ably to order without issue now.]
Gold Plated Glossy is the closest match the true badges, although it's very shiny. Almost too bright. Antique Bronze Glossy looks quite nice, just a bit on the dark side. Stainless looks decent. Silver will be smoother overall but it's pretty expensive, thus untested. All other materials are also untested.
*The backside has a 12mm x 1mm depression to adhere a magnet or pin (not supplied).