Where is Jimmy Buffett when you need him? Face it, Dallas is Margaritaville. So how do you choose between the perennial favorite ritas at Blue Goose and Uncle Julio's or the stylistically compelling artistry of, say, a Blue Mesa or Taco Dinner? We look for authenticity, and that is why La Calle Doce gets our vote. It's just the right amount of frozen--not overly icy or fluid. It's white, velvety, not too salty and plenty boozy. And it goes down smooth--that is, until that biting aftertaste grabs you by the throat and compels you to grab a chip and salsa--fast. Then it's back to the rita, a return trip to the chips, rita, chips, rita--all mixing and matching in a Mexican dance that can last until you're sated or plastered--whichever comes first.