Palermo is a traditional Italian area of Buenos Aires. It is known for its large parks. Also the American Embassy and the new Argentine president, Mauricio Macri, call Palermo home.
Since a few years, Palermo is the place to be in Buenos Aires. Surely La Recolleta and San Telmo have the touristic cachet. Palermo is a more honest area to have a beer or to meet for dinner.
Almost every corner is made up of a coffee shop, bar or restaurant. Party central are the bars of Plaza Serrano. Walk a few blocks away from Plaza Serrano, and you run into small and romantic restaurants.
Palemo got so popular that they started to distinguish between Palermo Palermo, the more traditional area with the large city parks; Parlermo chico where the president lives; Palermo Viejo and the more popular areas, Palermo Hollywood and Palermo Soho.
While, as a tourist, you have to visit, La Recolleta, la Boca and San Telmo, the place to be are the bars and quaint restaurants of Palermo. Find a place nearby to stay. It will save you a pretty penny. (If only I knew prior.)