KCSM-FM San Mateo, "The Bay Area's Jazz Station". Being a public radio, it has virtually no commercials, just jazz day and night.
KKSF-FM San Francisco, light jazz. Used to be my top favorite, but it seems since they were taken over by Clear Channel they tend to play the same tunes over and over, including Fat Burger's merciless butchering of Santana. Still, it can be relaxing and classy. KKSF puts out an annual CD called the Sampler for AIDS Relief - excellent collections of the top light jazz hits of each past year. And the proceeds go to a good cause.
KDFC-FM Palo Alto. Classical. Horrible commercials, but of course the music can be very stress-relieving. I like to have it on at work if I'm close enough to mute it during the commercial breaks.
KBLX San Francisco - "Soft and warm, the quiet storm". Black soul/jazz/pop, like a hipper version of KKSF.
Others - occasionally I'll tune in a C&W, Oldies, Rock, Mexican, or even a talk radio station for variety.