After having an iced coffee just about daily for the last month, I can easily say the best was Blue Bottle's New Orleans –style iced coffee from Ferry Plaza (the small Bay Area chain has seven other outlets, including one in Brooklyn). The cold-brewed liquid happiness is a much richer, smoother version of the chicory-laced coffee at the famous Cafe du Monde in New Orleans. This one is dark but not too acidic or harsh, with a buttery finish. It's definitely on the dessert end of the iced coffee spectrum—served over ice chunks with some sugar and a good wrist's worth of milk—but not enough to drown out the dark, deep, chicory flavors underneath.
Blue Bottle could be jerks and keep the whole preparation process a secret, but they don't. In fact, they were pretty smart to capitalize on us desperate caffeine addicts and sell DIY kits with the coarsely ground beans and step-by-step instructions. Iced coffee is so often a mediocre, guzzle-down experience, which usually does the trick just fine, but this one you savor like a hot cup, sip by sip.