Berkeley Ace Hardware's basement hobby shop has been the destination for most of the SF Bay Area's modelers for decades.
Even more reason to get there now. August 16th through September 13th they are offering 25% off all plastic models. The sale flyer states that only exclusions are items already on sale, special orders and train layouts.
They have a huge variety of new and old kits including models from collections, are very well versed and very modeler friendly (well, most of the time and a lot better that a couple of other hobby shops in the area).