The Museo de Arte Latinoamericano de Buenos Aires (MALBA) is definitely worth a visit. In the fashionable Palermo Chico neighborhood, MALBA is a great collection of art in a beautiful space. Don't get too excited when you hear the collection includes works by Frida Kahlo and Diego Rivera, since there is only one of each and neither of them are terribly impressive. Otherwise, the collection is great, and includes a nice variety of Latin American artists, including mural-style Manifestacion by Antonio Berni. I often get overwhelmed visiting huge museums, so the MALBA was perfect for me since it was easy to see the whole museum in a few hours.