The Frank Stella's are the best. They are all over the city and they always look amazing. Two of my favorites are the Saatchi and Saatchi lobby (pictured) and the Citi Corp building in Midtown.
If I lived closer to the West Village I’d go over to Jack’s every morning for a coffee and occasionally having what is probably the best chocolate chip cookie in New York (and it’s just a dollar!). Even though it’s rarely in my way I try to go here now and then, maybe in combination with a stroll down the beautiful Bleeker Street or to read a book sitting in their window.