I rode a Surly Crosscheck this weekend...I could totally see using that as a commuter bike. A friend of mine had that as her first bike...she used it for road and cyclocross races (how, I do not know...the thing is like a freaking tank!). She now uses it as her "Winter beater" with studded tires and is planning to put fenders on it and maybe a rack.

For a heavy bike it was very comfortable and not hard to keep moving pretty fast. It convinced me that I no longer want a cyclocross bike...I NEED one! I need more bike surface options than dry, well-maintained asphalt.