Is wine a virtue, a vice, or just a beverage? If you're not sure—and you're drinking some right now—you're not alone.Hard liquor tastes like trouble. That's why Sadie* drinks wine—soft, velvety white wine, preferably Riesling. The 34-year-old pharmacist loves the flavor, yes, and everything that comes with it: the gratifying snap of the cork, the beads of sweat on a cold glass, the buzz that still takes her by surprise.Three nights a week, often after a particularly punishing day at work, Sadie …