The second day my family was here we went to the flagship Macy's. Its the original "Miracle on 34th St" Macy's and its gigantic! Its 9 floors plus a basement, it spans the entire block and has 8 restaurants. We spent several hours there although we could have been there the whole day.
Outside Macy's is Herald Square which is a little green space with benches and statues. From here you can get a really good glimpse of the Empire State Building.