I first read about fixies in John Schubert's cycling book and he recommended them for winter/off-season training to improve your spin and to give a little variety to your riding. I never considered it while I was in Boston because my commute was hilly (Newton Upper Falls to Kenmore Square for you Bostonians). My commute here is fairly flat and traffic-free so a singlespeed/fixed gear is easy to ride. I just like variety in my riding especially in commuting where the route gets pretty boring. Last week I rode a different bike everyday.