Shopping is a part of travel whether you are buying CDs, a souvenir T-shirt or you forgot your toothbrush. But many times you never know where the best shopping is to be had, so you rely on the not always good advice of natives. Now Lucky, the magazine for shopping, offers guides to the best shops in cities across this nation and in a few others. From San Francisco to Miami to London, you can hit the pavment armed not only with your wallet, but with a comprehensive list of the best your destination city has in store for you.