Nature Aquarium in Santa Monica is nice.
Also, I wouldn't waste your time going to Sacramento.
Excluding wholesalers, I prefer Sac to LA and the Bay Area. It's easier to get to the stores, and they have WAY more square footage and better prices. Jo Jo stacks up well against most other stores in the nation, and Exotic has the tank space of a wholesaler...except that you can buy directly from them.
I second the recommendation for Nature Aquarium in Santa Monica. My favorite of the LA stores.