Whom to choose: A brother or the best friend who won’t party too hard after the rehearsal dinner―you do want him to make it to the ceremony, after all. In some parts of the country, it’s customary for the groom to choose his father.
Job description: Takes care of all bachelor events and provides support to the groom. Keeps track of wedding rings even if there is a ring bearer (you don’t want to assign that task to a four-year-old). Kicks off the toasts at the rehearsal dinner.
Caveat: Picking someone who gets along with the bride is a plus.