Hirshleifers
2080 Northern Blvd., Manhasset
Though it's not actually in the city, any trip to the Hamptons isn't really complete without a quick detour to Manhasset for a tour of Hirshleifers' racks. The selection here is superlative, from Lanvin sneakers to Stella McCartney dresses to Libertine blazers. It is the sort of place where you can easily tackle a season's worth of shopping—all while supporting one of New York's most compelling family-owned businesses.