We spent the month of March 2015 in Argentina. Initially we thought that would be enough for the entire country, but soon realized just how big Argentina is. We instead opted to spend the month in the North. We covered Buenos Aires, Mendoza, Salta, Iguazu Falls, and then finished with a few days at an Estancia (aka "working dude ranch.")
We expect to return in the future to explore the South of Argentina, including Patagonia.