I built a bike from the ground up as a dedicated commuter. Frame is a custom frame (steel lugged, very pretty).
Brake levers are cane creek - I like they way they feel in my hands - similar to the campy ergo shifters on my fast bike.
Brake calipers are tektro long reach, gives me room for bigger tires and fenders.
Crank and front ring are Sugino single speed stuff.
Rder is Shimano XT - I had a hard time deciding between RDER or IGH, could have gone either way.
Shifting is an ultegra bar end shifter.
Front hub is a Schmidt generator
Rear Hub is a Phil Wood.
Bike is just getting broken in (2000 miles), but I have been very happy with it.

Your choices will be dependent on your commute - hills, length of commute, do you ride in work clothes or shower and get dressed once you get to work etc.....