I and many of my cohorts who frequent the C&V forum and commute on our vintage bikes have found 70's & 80's steel road bikes to be excellent platforms for commuting. Especially touring-specific road bikes have ideal geometry and features, but the sportier models work fine also. If you do your own wrenching, they can be very inexpensive to acquire, modify to your needs, and maintain.
As for racks, in addition to a rear rack, I like to have some kind of front cargo device as well, be it a rack & trunk, panniers, handlebar bag, or any feasible combination. This helps distribute the load for better handling and dynamics.
I like and need to go fast, as my commutes have typically been in the 10-15 mile range, and on a good day, traffic permitting, I can reach nearly 20mph average speed, door to door.
