There is a few good ones in the area
 

White Oaks is a must see. They are in pacifica, which is about 15
minutes away from SF proper. You can check them out at
http://www.whiteoakorchids.com.

There is also a place called Shelldance that is also in Pacifica, but
I wouldnt go out of my way to go there. They have mediocre quality
plants and less than mediocre service.

If you get downt he coast a bit to Santa Cruz, you should check out
Maplethorpes. They have a lot of great slippers and are very
friendly.

There is also Orchidmania, though I have never been. you can check
them out at http://www.orchids.org/


Hope you have a good time in SF!