If I try real hard I can think of four or five yarn shops around Los Angeles County that I have never been to. That is, of the ones I know about. I wonder how many there are that I don't know about. I went to one on Saturday that I'd never heard of.
The Knitter's Studio in West Los Angeles is a small but well stocked shop. They have a nice selection of mostly upscale yarns like Koigu, Lorna's Laces and Alchemy. (I had to get some souvenir yarn so I got a couple of hanks of LL worsted in the color Mother Lode.)The yarns are arranged by color rather than weight or brand. I know a lot of people don't like that but I find it very pleasing. And you can tell right away if there's enough in the colorway you've selected instead of having to dig through a whole shelf or bin like in some shops that I won't mention.
The biggest problem with going over there is parking. It's practically non-existent or it requires a specific permit. And there are parking meters, even on the residential streets. We were lucky and found a place after only three circuits around the block. There are some jerks over there though.