Longchamp recently gave its bag collection a fashionable shot in the arm courtesy of designer Jeremy Scott. Now there’s a massive, three-level New York flagship (132 Spring St., at Greene St.; 212-343-7444) too, complete with a roof deck and a theatrical cascading lobby. Inside, beside the old, conservative Le Pliage bag, a wide range of more up-to-date shapes and designs (modeled by Kate Moss in the new campaign) hang from the ceiling and perch on maple display stands. Look out for the leopard-print Rodeo bag or the equally hip brown leather Idole Vintage satchel.