I'd suggest any decent randonneurring or touring bike for a commute. They aren't as fast as other bikes, but the focus of a commute is transportation and utility, not recreation or competition. Stable, comfortable geometry is good for after a hard day at work or biking to work the morning after a late night. And it's nice to have a bike that can handle stopping by the grocery store on the way home! A lot of rando bikes can handle a rack, usually even a grocery trip or light touring load, while being perfectly capable of taking out with an average group of roadies. I put over 20,000 miles on a secondhand Novara Randonee (REI) and I'd still have one if I could have picked up a frameset when the old one died.
As far as components, go for durability over speed. Tiagra level components can take you to work for tens of thousands of miles with no trouble. Most importantly, and I can't understate this, don't skimp on tires. With significant milage, #2 would be the rear wheel; have someone who knows what they're doing (and what you're doing with that wheel) at least check it over once in a while. Those are the two things that are most likely to get you to work late!
