Step away from the Hershey bar. Put back the Whitman's Sampler. If you want to buy your sweetheart some chocolate he or she will truly appreciate this Valentine's Day, go for the good stuff, chocolate prepared locally by those who make it their craft. As an aid, we chose confections from 10 of New England's top chocolatiers and put them through a blind, professional taste test in the latest installment of "Take 10."