Avoid Shimano shoes if you have broad feet!
I made the mistake of buying a pair despite warnings that they tend to be a narrow fit. 20 miles of riding left my left foot numb for a week. (It is slightly wider than my right foot. I just about got away with the right, though I think that would have suffered too on a longer ride.)
When trying on shoes, don't forget that your feet will probably swell slightly as you ride, especially on long, hot rides. Also remember that you will probably wear thicker socks in the winter.