For a real latte, I went to Baja Beans.
They're off a dirt road between Pescadero and Todos Santos, and a little hard to find but they have a sign off of Mexico 19. They get their beans from Oaxaca, and the roasting happens at their headquarters in Pescadero.
I heard they have a farmer's market on Sundays, but July seemed to be an off-season and they didn't have the market. Lots of open space outside, and I found a good flyer called The Onion Skin that's in English, and tells you what's going on around town.