Macy's headquarters store claims to be the largest retail store in America; expect to lose your bearings at least once. Fashion-wise, there's a concentration on the mainstream rather than the luxe. One strong suit is denim, with everything from Hilfiger and Calvin Klein to Earl Jeans and Paper Denim & Cloth. For cooking gear and housewares, the Cellar nearly outdoes Zabar's. Subway: B, D, F, N, Q, R, V, W to 34th St./Herald Sq.