The Metropolitan has two utterly amazing shows looking at some of the works left to the museum by pioneering photographer and art dealer, Alfred Stieglitz.
Stieglitz and His Artists: Matisse to O'Keeffe October 13, 2011–January 2, 2012
The exhibition features some two hundred major works with hefty helpings of Georgia O'Keeffe, Marsden Hartley, Arthur Dove, John Marin, Charles Demuth, Vasily Kandinsky Constantin Brancusi and other more unknown artists.
Smaller but at least as interesting is a related show of Stieglitz's photography collection.
Photographic Treasures from the Collection of Alfred Stieglitz October 11, 2011–February 26, 2012
I actually didn't know about much of this work from a group of photographers dedicated to pushing the creative and spiritual range of photography as a real art form.
Anne Brigman, Alvin Langdon Coburn, F. Holland Day, Gertrude Käsebier, Joseph Keiley, Heinrich Kühn, Edward Steichen, Clarence White are all in this show.
The Museum of Modern Art, also has a good ehibit, looking at some of the personal drawing collections that helped form the museum. Many of the people were not artists, but a few are. Hanging selections next to a profile of each collector helps one see the personal vision and taste of each.
Gifted: Collectors and Drawings at MoMA, 1929–1983 October 19, 2011–February 13, 2012
One important part was the collection of Kay Sage.
Another major show was at Gagosian Gallery, uptown.
The Private Collection of Robert Rauschenberg November 3 - December 23, 2011