Being unstoppably geeky, one thing Huw and I did in SF a lot was check out book stores. Mostly of the used variety because they tend to have cooler stuff. This is at Aardvark, which in my short experience, was the most charming. Although quirky charm seems a tad commoditized [note: not a real word] in bay area used books market my cynicism is always won over by cute pets. Especially pets that have jobs. And have their own workplace conveniences and caricatures.
We also visited Moe's in Berkeley where I ended up busting my nut the hardest and got 6 books on urban planning. Oh and Green Apple on the Outer Sunset which had nice t-shirts and tote bags.