i came to fixed gears through singlespeed mountainbikes. originally, originally, i started commuting geared just to be a better mountainbiker.
first a singlespeed commuter then to the fixed gear.
really i do it to stay in shape for mountainbiking. my commute has a big hill and i am quite sure it is easier (maybe faster) to ride when i am coasting, but for me, it's not about easy.
i do love bikeforums though, and i certainly appreciate all i have learned here about commuting and fixed gears here!