NPR had a piece yesterday on Oakland's taco trucks, the new foodie sensation (at least according to Chowhound boards.)
I wish the city had more traveling food sellers. Yeah, we have the farmers markets and all that, but there are lots of concert/club venues that could use some love too. Like near the Fillmore and the Independent.
Personally, I'd love to create a gourmet market truck with local produce and treats. That would be right up my alley.