I'm in Los Angeles. I see bike mess dudes on fixies ...but not tons of them like in SF. And it seems like the ones on fixies now are guys or girls who came here from another city...most of the guys I've seen down there for a few years have been MTB the whole time.
when I first moved to LA in 99, I used to see this bald dude that rode a bright orange KHS track bike (I think it was the one with the curved seat tube) near the beverely center mall...it was WEIRD to see this dude in LA especially near the beverly center mall of all places...I had just come from SF where you'd see them all over the place, to LA where there aren't that many cyclists, let alone any who ride fixed.
I've also seen a few punk rock kids in echo park who ride 'em...and another weird site was when I saw three punks riding down the Sunset Strip at 10:00 on a friday night, on brakeless track bikes....right in the heart of the weekend party crowds.
The other night I was driving near my house and I saw a guy way up ahead of me like 3 blocks up on a yellow bike...I couldn't tell if it was fixed, but something about the way he was riding made me sure it was.