We had just settled into a comfortable chair at a perfectly appointed table at Vincent's one recent afternoon, when we almost spat out our tap water. We're well-accustomed to the concept of the dessert cart, but the water cart? Sure enough, here it was, wheeled with as much pomp as the tarts and cheesecakes -- except on it sat a dozen or so varieties of water. "Sparkling or still?" the waiter asked, running down a list nearly as long as the restaurant's wine selection, and just as complicated. We ordered a Diet Coke instead, but sat back happy, relieved to know that even during one of the worst droughts in our city's history, Vincent and his water cart are here to parch our well-heeled thirst.