Fav art bookstore in the city (and the world?). Great place for inspiration and reference art, both new and vintage finds. Not very cheap but mostly quite worth it.
Has no sign outside, so you might miss it, but if you do happen to find it, you will feel like you have walked into the 1920's. Its very chic, with Black and white marble decor, candle light and ambience to go with a great list of cocktails and whiskeys etc.
One of the only things I enjoy about taking the subway these days is seeing the defaced ads on the L train. Whether it's random chance, high schoolers or street artists the result is always good.
One of my all time favorite shops. They have amazing succulents at reasonable prices. It's always a pleasure to stop in and see what they've got that day. Ched, the owner, is not only extremely knowledgeable but totally hilarious. Every plant has been personalized and anthropomorphized.