There is no doubt that Malbec is the grape on which Argentina's international reputation as a wine producing nation is founded. It is a difficult grape to which the climate and conditions around Mendoza are arguably ideally suited. It is also a grape which no other country in the world cultivates to anything like the same degree - and certainly not for production of single grape varietal wines.
Another varietal used in Argentina is Cabernet Sauvignon which fares best in warmer climates, and benefits from a long ripening season. In Argentina Cabernet Sauvignon is usually picked towards the end of the harvest, in late March.
While white grapes are grown - Torrontes and Chardonnay in particular - Argentina is, predominantly, a red wine-producing nation. The hot, dry climate is simply better suited to red grapes (although this may not be the case in the future, as growers look increasingly further south for good grape-growing land).
Chardonnay and Pinot Noir are classically used for Sparkling wines.