Only a few stores occupy an entire city block; Macy's is one, and this New York institution is another. The main floor is a stupefying maze of cosmetic counters, mirrors, and black walls. Get past this, and you'll find some good buys on dependable designers, bedding, and housewares. Don't mind the harried salespeople or none-too-subtle promotions -- chalk it up to the Bloomie's experience. At this writing, Bloomingdale's had just opened a SoHo branch, at 504 Broadway between Spring and Broome streets. Subway: N, R, W, 4, 5, 6 to 59th St./Lexington Ave.