best of Friends

something got me thinking. what are best friends? is there a line differentiating best friends and family? who draws the line? when do you have the right to call someone your best friend? does the time come when you stop calling your best friend "best friend"? if your best friend is of the opposite sex, can he/she become your spouse as easily as if he/she were not your best friend? do matters become more complicated between best friends? how do you find one?