A flat bar has one advantage in traffic-congested areas, that your hands are always on the brakes for urgent stops. I suppose you could always add "cross brakes" to a road bar if you wanted that continuous access. It's a second set of brake levers that mount on the horizontal part of the handlebars, on both sides of the stem. (They're different from and superior to the brake extension levers seen on cheap 1970s road bikes).
I'll echo others...the most important features of a commuting bike are the racks and fenders; and 700c slick tires (ie. little or no tread) are best for pavement commuting. Carrying your stuff on a rear rack is much more comfortable than in a back pack. The bike is more stable because the weight is lower, there's less back strain, and much less sweating.
Last edited by cooker; 06-22-06 at 01:07 PM.