Use

My good friend Matt rides a brakeless fixed-freestyle setup:

While Matt has plenty of other bikes which might be more suited to the daily commute, his Scrambler tends to be his main ride on the mean streets of San Francisco.  Big hills and no brakes can lead to some interestingly worn pairs of shoes:

That divit is a result of using a hasty foot against the wheel as a brake... 
To all you crazy folks: ride safe out there