We are one of the countries with the largest immigration in the world if you consider immigrants per-capita. This is consistent with our history, we used to be a favorite destination for Europeans a hundred years ago and now for fellow Latin Americans. There are always some right wing idiots complaining, but most of the country welcomes immigrants. Also in the last couple of years we are again a favorite destination for Europeans, you see them everywhere and not just as tourists.

More info, but a bit outdated: http://en.wikipedia.org/wiki/Immigration_in_Argentina

  "Nearly a million permanent residency applications were filed from 2000 to 2008[]"

And we are just about 40 million. :)