Schwalbe Marathon Plus - good traction, supple ride, great flat prevention

Specialized Armadillo - great flat prevention, ride is a bit harsh, traction is so-so in comparison to Marathon Plus

Continental Gatorskin - good traction, flat prevention not as good as Marathon Plus or Armadillo, ride is not quite as nice as marathon plus (however, I have the 25 gatorskins on my road bike and 28 marathon plus on my commuter - it could be that the wider tire makes the ride nicer on the marathon plus, and not necessarily the tire itself.)

My favorite commuting tire is the Marathon Plus.