I change commuters during the year dependent on weather, how dirty the roads are, lighting needs and how much I want to preserve the machine. I am the original owner of all these bikes. The following is the usual scenario:
From October-November and February-April I ride a Davidson Discovery touring model with Shimano 600, Karrimore rack and barcons. I think I bought it when Elliot Bay Bikes opened in the 80's. It needs paint and would stop better with cantilevers.
December-January-Bridgestone Radac fixed gear. My commute is hilly with a couple of hills in Seattle and on Bainbridge that are hard on the knees both up and down or I would commute on this bike all winter because it fits great.
May-September - '83 Eddy Merckx Team Issue (DeRosa style with flat crown, etc.) with NR Campy, Dia-Compe 500 brakes, 28 hole clinchers with Mavic hubs, etc.
All have fenders for the rainy weather here.
Bainbridge Island, Wash.