Always stock tequila for margaritas, but just check to be sure the label says 100 percent agave. Casa Noble Reposado ($45-$50), made from all blue agave, then aged for a year in French white oak is a solid start. If you're a tequila connoisseur, you should have a few bottles, plus a mezcal, tequila's smoky cousin. This list of the world's best tequilas is a great place to start. And that ritual of lime and salt to knock it down? Suitable for the cheap stuff, but this deserves more respect.