From three pages of response, you've probably figured this out, but road bikes of 80's vintage make especially nice commuters. I'm alternating between two such bikes at the moment. They tend to have more relaxed geometry in road bike form, and longer chainstays that keep you from kicking your panniers. If they were originally equipped with 27" wheels, you can switch to 700s, use long-reach brakes and have huge clearance for larger tires and fenders. And lots of the 80's road bike have eyelets for rack and fender mounting, at least on the rear, and often on the front.