Ya know, the way people talk, it seems like there are roving bands of bike thieves looking around, cable cutters in hand, just waiting for people to leave their bike for a second...

Even in the "bad" neighborhoods of Chicago and Indianapolis when I lived there, a cable lock through both wheels and frame, a U lock for the back wheel and a small chain lock on the saddle was good enough to keep most any bike safe. If that doesn't do the trick for you, perhaps your commuter is a bit too high-visibility.