I'm mostly posting this to turn flyertalkers on to a new columnist over at salon.com, Francis Lam, who's a young professional chef and a not-too-terrible writer.
Here's his latest, on vinaigrettes.
So a vinaigrette is a dressing (or sauce, technically) that plays specifically on the balance between acid and oil. For me, a true balance is one where you really kind of can't tell where the oiliness begins and the tartness ends, and the two seem just to swirl around each other. But some people prefer a vinaigrette that hits you sharply with its sourness in the beginning, mellowing to the richness of oil, and there are those who like theirs mainly slick and rich, with a note of tartness just to lighten things up.