I love bike shops. I can hang out in a bike shop for hours. And I like discussing the difference between bike shops. Different shapes, sizes, interests, good points, bad points. I won't always like the end result but the process is most of the fun.
There is a new store in Noe Valley, I walked in yesterday and checked it out. Review will be forthcoming. For now, 2 shops I use with some frequency.
Warm Planet Bikes - 4th/Townsend, SF. Operated by "Kash", someone whose writings I've been able to review on the sfbike mailing list (open with care, it's frequently off topic and there is plenty of ranting). The major plusses - opens at 7 AM, closes at 8 PM, and will VALET CHECK your bike for free! As a Caltrain commuter this place is a huge plus. Check your bike and take the train. Check your bike and have them work on it while you are at work. Flat on the way to the train? Having what you need at the train station is a big bonus. Kash's operation definitely is focused on the commuter. All the bikes in the shop are folders and there's no racks of spandex jerseys or Sidi Shoes. Look instead of fenders, locks, lights, racks. This shop is about using your bike to get the job done. The first time I went there I asked for a 700x23 tube, Kash replied "Presta?" I laughed - "Is there any other kind?" Of course there is but I definitely live in a Presta world. But Kash didn't have a 48mm stemmed tube! That has been corrected, but he doesn't have my favorite T9 lube (I just don't like Tri-Flow). This store is indispensible and I'll give them whatever business I can.
In Sunnyvale is Walt's. I used to *hate* this store. It was by the Caltrain, which was great to get a tube in a pinch but all the bikes were junk, the store didn't carry much useful stuff. I sort of thought they basically catered to 12 year olds and people who could not afford cars. A group that needs to be served, but I had not much use personally. Certainly I would not leave my bike to be serviced there.
What a change a few years can make. The shop has been remodeled, the bike range has been expanded, from low end utility bikes to high end road bikes. A much better selection of clothing, tires, helmets, tools, etc... I got my T9 lube there today. The best part? They have an *incredible* selection of used bikes.
There was a very cool old school Puegeot with downtube shifters, 7 speed for under $200. Raoul from the Caltrain tells me they have a "loft" with all sorts of treasures. All the bikes look to be in very good shape, if a bit vintage. Nice. Their service has upgraded very well, I highly recommend this store.