In a few months my daily commute will be shortening down to two miles. Since I have to wear dress clothes (ties, slacks, etc.), I've always worn bike gear and changed at work. But with this short distance, I think I'd like to save some time and effort and just ride to work in my dress clothes (and rain gear over the top of that in the winter).

I'm trying to figure out the perfect commuter for year round riding that would be comfortable to ride in dress clothes. I think the ride is flat enough that I can get away with a single speed bike to cut down on maintenance and also to keep the bike cleaner. The ride will be mostly on residential streets and bike paths.

So far this is what I'm toying with, and I'd love to hear your feedback:

-Aluminum track frame with carbon or steel fork (depending on what I end up buying)
-Coaster brake in the back to simplify the design, on a 700c wheelset
-I've considered putting a disc brake on the front as a backup, but I'm going back and forth about whether I want to add the clutter and maintenance of another brake. Part of me thinks if I did his, maybe I might as well just run disc brakes front and back, but I've kind of liked the idea of just the coaster brake.
-Originally had thought about using drop bars, but maybe something more upright would be a better idea for comfort while riding in dress clothes?
-Full fenders and a chain guard to keep things clean

Any other thoughts?