Source: Acme Bread Company, Ferry Plaza Marketplace, 288-2978; or 1601 San Pablo, Berkeley, (510) 524-1327
The reputation of Acme breads has not suffered from their ubiquity, 27 years after Steve Sullivan founded the bakery. In fact, if one were to claim that the Bay Area has a unique style of hamburger, it would have three essential characteristics: sustainably raised beef, good mustard, and an Acme bun.
While Acme's batards, baguettes, and herb slabs can be found in most of the city's grocery stores, the Ferry Plaza and Berkeley bakery stores carry a number of more difficult-to-find breads, including the "sweet" and "sour" loaves ― sandwich bread baked from Acme's two baguette doughs.
The sweet loaf, which I bought yesterday, has the same golden, slashed top as a baguette or a boule; my bag squashed the loaf during the trip home, but the bread cracked rather than crumpling, its surface fracturing into appealing, glossy facets. Howevever, the first slice was a disappointment. Its flavor was flaccid (you don't eat a baguette for the center, do you?), and its airy crumb and loose structure meant that any sandwich I made with it would soon be dotted with blobs of mustard and mayo that had squished out through the airholes.
Then I put a second slice in the toaster.
Aha! The nuttiness of the baguette crust emerged. It's toast that wants a little butter and honey, toast that's perfect for BLTs and club sandwiches. As long as you respect the source of the bread of course ― with pastured meats, farmers'-market vegetables, and homemade mayonnaise.