We all know the stereotypical movie director is the guy with the beret, and riding pants,why?

The stereotype was patterned after Eric Von Stroheim. Most directors are regular people. Von Stroheim was rather striking and easy to parody. He wore a beret, riding breeches had a thick German accent and a monocle. He started back when the business was young so the stereotype was established early and stuck. And he was the origin.

maybe just like the stereotypical bicycle rider wears their little spandex onesie
maybe just like the stereotypical nurse wears scrubs
maybe just like the stereotypical coach wears windsuits
maybe just like the stereotypical.......................

What stereotype are you talking about? Like in Scooby- Doo? That may just be a silent era thing, but that image of a director has been dead for a long time.

Yeah, that stereo type is more of a parody these days.. the current "stereotype" would be the dirty baseball cap with either a t-shirt or a sweat shirt.. and jeans.. with any old sneakers/tennis shoes that happen to be lying around..
Classic example being Ron Howard:
http://www.filmweb.no/bilder/multimedia/...
and when they need to dress up.. there is this:
http://www.deadlinehollywooddaily.com/wp...