Kenneth Pool   New York Magazine Pick   The Gown: Strapless embroidered gown with dropped-waist bodice and crystal embroidered panel-back train.   The Price: From $5,600.   Where to Buy: Gowns range from $3,500 to $6,500 and can be purchased at Saks Fifth Avenue, Bergdorf Goodman, Kleinfeld, and Wedding Salon of Manhasset.