OK let's try to answer TQ's question.
Congratulations! You're heading down the path that I was on 6 years ago. It's a real adventure, and I have no regrets!
First, in order to ship any quantity of stuff here, you'll need a resident's visa. Since you're retiring, you can probably arrange the visa relatively easily. If you can't get a legal resident's visa before you move, you should probably plan to bring whatever you can carry on the plane and no more.
If you will have a visa by the time you arrive, you can ship personal effects here exempt from import duties during the first 6 months from the date of your first arrival on the new visa. To explain, let's assume you apply for your resident's visa at the Los Angeles consulate and it's granted on 12/01/2012. You then take a trip here to check on your new home, arriving 12/10, and then you move for good on 2/01/2013. December 10, 2012 is the start date for your 6 month period, so all duty-free personal effects must arrive in Buenos Aires by 6/10/2013.
Next, be aware that the authorities will probably require a
seguro de caución to guarantee future payment of duty on your personal effects. Although these goods aren't subject to import duty, if your visa is temporary rather than permanent, you'll be required to buy an insurance policy that will pay the deferred duty in the event that you never achieve permanent residency or you leave the country without taking everything you brought in duty-free. The annual premium is about 10% of the value of your goods as determined by customs, and the
seguro must be renewed each year until your residency becomes permanent - typically on the 3rd annual renewal.
So if you still want to send personal effects, you'll find that the only economical way to do it is by container on a ship. Any international moving company can arrange this, for delivery here usually in about 6 weeks. (The moving company will also deal with local customs and help with the
seguro de caución btw.) There's a basic fixed cost to shipping a container; the only variable costs are charges for packing and moving more or less stuff from your home, delivering it here, and insuring it in transit. Since this variable part of the cost of a move is fairly small, it makes sense to send anything you think you might want here, up to and including even a car.
That said, consider that electricity is 220V here, so think twice about the US appliances you can't live without. Most electronic gear (TV, audio, computer, etc.) will work on 220v without problems, but anything with a motor (like a refrigerator, food processor, or mixer) or that generates heat (like an toaster, iron. or hairdryer) will require a fairly large transformer, and these tend to get in the way a lot, especially on kitchen countertops. Aside from maddening and unpredictable shortages, you can find adequate versions of most countertop and personal appliances once you're here.
An electrician who worked here a few years ago described a house he had re-wired for US expats, where he installed a huge transformer that powers all of their US appliances, including refrigerator and microwave, from the electrical outlets. Of course this is not a trivial job. Consider also that your US appliances are unlikely to last forever, so you would probably want to have double wiring and double outlets to power both your imported 110v devices and whatever new 220v appliances you buy here. At minimum, you would need some 220v outlets for lamps and the like.
Electronics are very good candidates to bring here, however, even though customs will declare a high value for them, which will raise the cost of your
seguro de caución. The local market typically sells only prior-generation TVs, computers, etc. at prices double what you pay in the US.
In general, Argentine manufacturing is geared toward the working to lower-middle classes. Anything imported is expensive, and availability is always a question. (At the moment it's a real problem!) So depending on your tastes and the quality of what you already have, you may want to bring linens, tableware, glassware - basically anything that might be considered a "luxury" item in a working-class household.
Kitchen stuff - if you have really good pots and pans, bring them. You won't find cookware anywhere near the quality of All-Clad or Calphalon here. Same for good knives. Good flatware, dishes, and glassware are available, but items tend to go in and out of stock making it difficult to maintain matched sets of anything, and prices for better items are considerably higher than you would pay in the US. If you like to cook and have a gas range that you really like - say a Wolf or a Viking - you might consider shipping that as well, since the best stoves in the market here are basically junk compared to high-end US models.
Books - you won't find a good selection in English here. If you prefer to read in English and you return to your Raymond Chandler novels twice a year, bring them. Or maybe a well-loaded kindle or a iPad.
Artwork is personal, so that question is hard to answer. There are very interesting Argentine artists exhibiting around town, and prices for art works tend to be lower than for comparable works by emerging US artists. But it's really a question of your tastes and preferences.
Furniture - I would plan to buy new here rather than ship. You won't find an Ikea-equivalent in Argentina, but you will find showrooms and furniture makers that can reproduce anything you've ever lusted for in a decorator showroom (bring pictures!) for a fraction of the US price. Only quibble is lack of availability for good upholstery fabrics, although these are easy to carry when you return from trips abroad, and fine leather is cheap here.
Returning to my mention of a car, if you will want a car here and you're shipping a container, consider bringing it. Cars are much more expensive here than in the US. For example, a Civic sedan is a luxury car here, with prices between U$ 28-34,000 for models generally less well equipped than in the US. In contra, if your car is a model that's not manufactured in Mercosur, be aware that service and parts availability may be a problem.
Finally, in no circumstance should you consider moving personal effects by air freight. The customs crew at Ezeiza is notorious for overvaluing items and holding up shipments arbitrarily. By the time you overcome the bureaucracy and get air-shipped goods released, a container could have been delivered at far less cost.
Feel free to send me a PM if you have specific questions.
