Warren Buffett once called the cigarette the perfect product: "It costs a penny to make. Sell it for a dollar. It's addictive." Much the same could be said about coffee today. Even a costly coffee drink -- Starbucks sells its lattes for about $3.50, depending on the location -- consists of little more than a cup of water, a splash of milk, a spoonful of coffee grinds and 30 seconds of labor. Starbucks has managed to turn its customers' craving for caffeine into a $6.4 billion a year business. It already has about 6,000 company-owned coffeehouses and claims to open...