For first-timers, the big sights are Buenos Aires , Iguazú Falls , and Patagonia’s Moreno Glacier . Since most will arrive in Buenos Aires, this simplifies logistics, but great distances mean that flying to Iguazú and Patagonia is unavoidable.
If you have just seven nights, figure at least two in Buenos Aires (at the beginning and end), two in Iguazú, and three at El Calafate, gateway to the glacier. With two or three extra days, you could spend more time in the capital, take an excursion to the Fitz Roy sector of Parque Nacional Los Glaciares , or perhaps overnight at an estancia near Buenos Aires or El Calafate.
Arrive at Aeropuerto Internacional Ministro Pistarini (Ezeiza) and transfer to a Buenos Aires  hotel, with the afternoon free for sightseeing.
Catch an early-morning flight to Puerto Iguazú , with the afternoon at the falls; if the timing’s right, take the full-moon tour.
Take an excursion to the Brazilian side of the falls or, alternatively, hike the rain forest on the Argentine side. Or, visit the historic Jesuit mission of San Ignacio Miní .
A morning flight back to Buenos Aires and on to El Calafate  eats up most of the day. Take an evening excursion to a nearby estancia for an asado.
Plan for a full-day excursion to the Moreno Glacier in Parque Nacional Los Glaciares .
Travel overland by bus or rental car to the Fitz Roy sector of Parque Nacional Los Glaciares , with accommodations at the hamlet of El Chaltén . With an early arrival time and good weather, there’s time for a swift hike to view the glaciated needle of Cerro Torre.
Stupendous views of Cerro Fitz Roy make the strenuous full-day hike to Laguna de los Tres worth it. In the evening, return to El Calafate.
Spend a relaxing day at an estancia like the rustic Estancia Nibepo Aike or the more luxurious Eolo Lodge, on Estancia Alice .
Explore Buenos Aires during the day before your evening flight home.