One of my favorite stores ever, if you're veg or just health-conscious and need groceries in SF, you must go to Rainbow and experience its wonder.
All-vegetarian (I believe with the exception of pet food; I know they do offer V-dog vegan dog food), with many specialty vegan items, they have the widest variety of organic, healthful ingredients. They also have a large vitamin and personal care/beauty section, along with small areas of books/gifts and home goods (mostly cooking implements). I especially love their candle and soap sections :)
They have a fantastic bulk section where you can find all the spices and dry goods your heart desires. They have lots of both dairy and non-dairy gourmet cheeses, along with an olive bar and fresh pasta selection. Their produce section is thoughtful -- organic and local as much as possible. I do find that while most of the store offers competitive prices, the produce is on the expensive side. They do have a sale section I love -- after the bulk bins on your left entering the store, there's a whole area for items on sale, which is fun to explore and try something new.
They also have a small garden area with some fresh plants and potted herbs seasonally available.
I've tried to describe it so you won't have to take my word for it -- Rainbow has everything you need or want, and you will probably want everything they have after a visit.
It's a truly hippie place, where most people remember to bring their reusable bags but no one's pretentious about it if you didn't. You might ask to use an extra cardboard box to carry your things if you don't want to buy paper bags.
They have a parking lot but at busy times there's a line to park, so it's best to try to come at an off-peak hour. And you will want to drive here, or plan on getting a friend to take you and your armfuls of amazing treasures home.
Updated from previous review on Sunday April 06, 2014
Cons: Might be overwhelming at first, Waiting to park