I seem to have a different perspective than many commuters. I don't mind fixing the occasional flat in order to ride lighter, faster-rolling tires. I generally commute on 700x25s and have commuted for years with perhaps 1-2 flats/year riding Conti GP 4000s, GP 4 Seasons, Michelin ProRace, Vittoria Rubinos and the like. During that period, I have tried heavier, more flat-resistant tires such as Conti Gatorskins, Panaracer Paselas -- and I always get frustrated by their slowness and poor ride quality after a few weeks and take them off.

My route has a lot of hills but relatively good pavement, so I pay a real penalty riding heavier, poor rolling tires. However, my touring bike and cross bike are fitted with larger (32mm+) tires and I commute sometimes on them. Both of them have tires that are relatively light for 32s -- Vittoria Randonneur Hypers and Rivendell Jack Brown (greens). Both of those are really nice rolling for wider tires and not much slower than 25s, but worth the extra weight because they ride so much better with fat tires.