We spent two full weeks in Argentina the begining of March and had a wonderful time!
If you don't want to read all the stuff below, here's the short version: The people are terrific. Engage as many people as you can in conversation. Make fiends, it's easy and rewarding. Try to stay three nights at least in each place you visit, it helps in meeting people. Don't worry about places to eat. Find a place that appeals to you aesthetically and walk in. The food and wine are bound to be great - and cheap! See as much of the outdoors as you can. There are a lot of exciting, interesting cities in the world, as there are in Argentina but, Argentina's 2nd best asset, after its people, is the land itself. See it.
Now, the long version:
We spent three days in Buenos Aires. It's not Paris or New York but we'd like to go back. There are a million guide books and websites discussing BA. I think it's especially fun if you are young and want to party. There are loads of bars and clubs packed with good-looking friendly people and it won't cost you an arm and leg. There are no $12 USD martinis in BA.
Next we spent two days cruising the Parana Delta with Santiago on La Barba. What fun! The night was spent at Los Pecanes B&B where we had excellent food and felt at home with Anna. The delta is a very unique area and different from what most peope see when they visit Argentina. Santi is an excellent host and conversationalist. The best steak we had during our trip was for lunch on La Barba - and that's saying a lot! We love "messing about in boats" so the pace of this trip and the way of life in the delta was very relaxing and serene.
Next was three nights in San Isidro, a suburb of BA. This is a very pretty area with lots of colorful storefronts, a cathedral, a costal train that runs between Tigre and BA. We stayed at Hotel del Casco which might just be the most gracious place we have ever stayed. Try Frenet restaurant next to the Irish pub near the train station. A mile or so south of the center of San Isidro is a very upscale neighborhood where you can buy your Mercedes or Ferrari for the rest of your trip.
Now we begin to fly. The distances are great in Argetina. For example, it's 14 hours by car or bus between BA and Iguazu or BA and Mendoza. We used the "Visit Argentina" plan of Aerolineas (and yes, we did get caught up in a strike). If you have the time, the intercity busses were very highly recommended by everyone we spoke with.
On to an estancia in the mid-sierras south of Cordoba. This is one we want to keep to ourselves as a secret (with great apologies to our hosts!) This area, also known as the Cuyo, has beutiful climate, terrain, lots of water and splended views. Champaqui is the local mountain here and worth the six hour hike to the top. There is a huge National Park on the top of the mountains with excellent places to horseback ride, para-glide and hike. If you imagine what Califorina must have been like 100 years ago, this is it. I'd suggest renting a car in Cordoba and exploring south. Corodba, is a university town so there are a zillion students in the city center. Read up on the town of Belgrano and its WWII connection.
Then to Iguazu. This is a must see, one of the great wonders of the world. And, as you would expect, jammed with tourists. Two days here should be enough. Take the boat ride into the falls (wear a swim suit). If you stay at the Sheraton, note there is a public bus that will take you into town. The stop is near the park restaurant. It will save you the $80 peso cab fare!
Then to Mendoza. Absolutely make reservations for winery tours. Buy a few bottles of Malbec at home and then search out the Bodegas where it's made. This is a good areas to rent a car. There's a lot to see, especially the road to Chile and Aconcagua. Try river rafting on the Mendoza. It's a fun half day outing and you can stay for drinks afterwards in the bar restaurant.
If you get stuck between flights at EZE, you can eat in the upstairs restaurant. It's excellent - really! And you'll have a full filet mignon meal w. wine for less than two drinks at LAX.