Pref somewhere near Walnut Creek, but I'm willing to travel to find a cheap bike... I just want something that I won't exactly beat myself about getting stolen if I'm unlucky enough for it to happen to.
I really only know of Performance, a few local shops in Danville/Alamo, but not much else around. The place I used to go to in Martinez closed =\.
There are several places in Davis actually.. don't remember their names but I recall seeing 2 shops loaded up with nothing but old used bikes. One was near the 7-11 on L. The other was right downtown near the BofA.
The one spotted in Davis near the 7-11 on L may have been the Davis Bike Collective http://daviswiki.org/Davis_Bike_Collective . This is run by the same people who are trying to bring bicycling back to Davis. It would be nice to see Davis return to its former glory.