I run 28mm tires on my commuter in the three-seasons. My new wheelset uses Velocity's VXC rims, which are 24mm wide. (Sorry, the VXCs are for disc brakes only.) The difference in ride is quite noticeable.

This is provided you also ignore the advice in the Road Forum about triple-digit tire pressures. See this thread for sane inflation pressure recommendations. There is also a good article on the subject here.

The additional volume contributed by the wider rims has also allowed me to reduce my tire pressures further, which smoothed the ride even more. Between the two, my commuter rides really sweet.

Based on my experience, I'll be using A23s on my roadie's next wheelset.