One of the many leather/fetish stores in the Folsom St. district, Leather, etc. strikes me as a store more oriented toward a heterosexual clientele than most. Even so, their quality is reasonable, and their prices are much more affordable than other stores. For clothing, go here. For high-quality equipment, see Mr. S.
...give up Netflix! GreenCine has more documentaries than its larger, multitentacled counterpart, and it has porn, too! Foreign language films, anime...it's all here. It's slightly more expensive, but worth it, especially because, if you live in the Bay Area, you get new DVDs the same day you send old ones back.
...make sure you stop in here at least once. Its reputation as one of the best bookstores in a city full of great bookstores is well-deserved. It is a little bit crowded, but you'll hardly notice if you're as into wandering around San Francisco's tiny shops as I am.
Even if you're not, this place has an historical value that makes seeing it at least once worthwhile, especially if you're into Beat poetry. Ferlinghetti started the place, and Ginsberg's "Howl" was published here.
If you're an academic, this is paradise. Every book that comes off of a major university press is either here or just waiting to be special-ordered from here. The prices are on par with what you'd expect to pay for a university-press book--not great--but when you need that obscure discussion on medieval tapestry, the politics of Beethoven, or a Foucauldian discussion of just about anything, here's where to go.
So it's disorganized. So the sales staff is less than helpful. So what? If you can find it, the book you're looking for in order to finish that paper or complete that collection is in here somewhere. And it's probably cheaper than you thought it would be, too. Set aside an hour or so and wander around the multiple floors. Dedicated book-lovers will love its used selection, if not its barn-like atmoshpere.
Cody's is by far the largest independent bookstore I've seen in the state, and I've only seen its like in the form of Powell's in Portland, OR. It continues its long history of opposition to censorship and flexible special-ordering. Although its prices are not the cheapest in town, you'll feel good for supporting a community fixture.
This surprisingly large store has virtually every kind of (non-video) game imaginable, from the old ones your parents remember playing to specialty historical ones to card games. I personally like war and strategy games, and there are enough variations on a theme of RISK (and the original RISK as well) to keep me happy. Also check out their D&D books and figurines.
Do you need fresh bread or pastries to impress your friends at a dinner party? How about just breakfast? Arizmendi is a bakery cooperative that has a limited, but delicious selection. For sweet things, try the chocolate roll, and for something more hearty, try the asiago roll. They also have various vegan muffins and breads.
For this well-known sex toy shop. This is a place that you actually could take your mother, your minister, your best friend, AND your lover. The store is clean, well-lit, and unashamedly right on San Pablo--no weird "Entrance in Rear," no tiny signs, no trying to blend in. It's run by the workers in a cooperative, and they make it their first priority to make everyone, regardless of race, gender, sexual orientation, or level of embarrassment feel comfortable in their store. Salespeople are helpful but not intrusive, and you'll find (most of) what you want.
The goods are of uniformly high quality, since the cooperative values its reputation and makes sure everything actually WORKS before agreeing to sell it. Prices are not cheap, but not terrible.
People looking for BDSM gear should go to Mr. S in the city, though.
Yes, Virginia, this is a completely gay male porn shop. However, they are quite welcoming to all sorts of people, something that is not necessarily true of all gay adult stores in the city. This one has as many permutations of hot boy-on-boy action as you can imagine, although (fittingly enough) the Folsom Street location is more specialized in leather. As is normal for a place like this, they do sell a few toys as well, though you are better off getting those elsewhere.
If you live in the area, RENT.