I live in Southern California and most of the people who ride bikes to their jobs are blue collar. They are usually gardeners, construction guys, restaurant workers etc. I'm sure 15 minutes into a job like that you're pretty sweaty, so who's gonna care or notice if you're sweaty right from the start? And unless they have to wear a uniform at work, all of them wear their regular clothes.

I work in an office and I wear my regular clothes only because I don't want to fuss around with extra clothes. And also because I want people to see me as a bike commuter so that they consider it for themselves.