Hodo Soy makes some quality products, from their basic tofu, soy milk and yuba (tofu skins) to flavored versions of all of those. The Hodo Soy stand in the Ferry Building also has chocolate pudding (flavored with chocolate from a nearby chocolate maker) and some cold curry wraps and sandwiches.
I got the pudding ($4) which was really tasty, but felt expensive considering the small portion.
They also give you free samples of anything, so don't be shy about asking to try something out before you buy. Their spicy yuba dish is great, for example.
Hodo also sets up at the Berkeley Farmer's Market and the Palo Alto Farmer's Market. At the Ferry Building, they have a small stand inside, as well as outside.