I commute every day, and most days ride an older Specialized Roubaix, which is a carbon road bike. It makes a great commute, although I do park it in my office building, and wouldn't leave it locked up on the street.

I use a Topeak beam rack to carry my stuff, which works nicely with the dedicated bag:
http://www.topeak.com/products/Racks/MTXBeamRackV-Type

However, I did change the seatpost to an aluminum one, since you have to torque the beam rack clamp pretty tightly to keep it from swinging around. Not sure if that was really necessary, but I was concerned about squashing the carbon post.