A slice of Fugazetta from La Mezzetta.
Thats what I want from Argentina when I am in the States...
While you are at it, bring me some Terma Patagonia.
But I bring back all kinds of things that are Industria Argentina, that americans find entertaining.
Fernet, Hesperidina, Mate, and Chimichurri all have been popular with my friends- although they require explanation, and, usually, preparation on my part.
Everybody seems to like a Hesperidina with tonic water, a slice of lime, and some crushed fresh mint leaves.
I buy the little metal tins of chocolate from Casa De Chocolat on Corrientes- its not the best chocolate in the world, but its very typical, and the presentation, in the old stamped metal tins, is such a novelty to americans that they love it. Plus, it all always gets eaten- its not THAT bad.
My Futbol playing kid loves argentine jerseys, and the variety of them available in BA is far beyond the simple national team jersey that is all you can usually find in the US.
Pinguinos are another thing that are so totally argentine that they are fun to bring- Calma Chica, in Palermo, has the modern, minimalist white ones, very trendy.
CD's of contemporary argentine music are very popular with my friends- particularly all the new postmodern tango stuff like Bajofondo, Tanghetto, Tango Crash, and Gotan Project. Tonolec, Juana Molina, Gaby Kerpel, and Axel Krygier seem to go over big as well. Rock Nacional, not so much- too time and place specific, and too dependent on actually understanding the lyrics. Since Juana isnt really saying words anyway half the time, they translate better.
Carpincho house slippers are nice. comfy, soft, and not fitted to a specific slze.
Books about BsAs, particularly photo books, are popular as well- the Art Noveau book always wows people, as well as some of the books of historical photos that are available. Everyone outside of Argentina thinks Buenos Aires looks like Olde Mexico, and are amazed seeing things like Palacio Barolo.
Since I am a textile person, I always buy yarn anyway- but argentine yarns are high quality, cheap, and desirable to any knitter or crocheter. Many of my friends covet the stuff we bring back from Scalabrini Ortiz y Cordoba.
A lot of sweaters and scarves around here are the result.