honestly, a proper road seat IS comfortable. if you want to commute on a roadie, go steel or aluminum, as you're more likely to find lugs for a rack on those. the jack-of-all-trades seems to be the cx (cyclocross) bike thanks to drop bars, somewhat aggressive position/geometry, and the ability to fit fatter tires.

how are your roads? give it a shot. if you get a road bike and don't like commuting on it, you have a road bike. hooray! road bike! /red stripe commercial impression