When I lived in Madison, I lived 4 blocks away from the Mifflin Street Co-op, and I shopped there regularly. In particular I liked their selection of spices and the gourmet chocolate chips they carried. (I tended to skip the Mifflin Street Block Party, though; but you can see some photos of the 2005 party.)
Apparently the co-op may soon close its doors, which would be a real shame.
One feature of the co-op was the impressive mural on the side of the building. Here are more pictures of the mural.
(via AgentXpndble)