I know everyone's having a jolly good time bashing how stupid Americans are for the weaknesses in their phone plan options, but what about the strengths of what AT+T offers? I will focus on non-data users, where the US offerings are particularly appealing. First of all, it can be really cheap. If you get a few friends on a "family plan" with AT+T, you can basically get unlimited voice calling for a family of four for like $20 per person per month, including free phones for all. Talk to anyone anywhere in the US, any time of day, as much as you like, and don't pay more than $20. Ok now, I'm stretching the truth a little, because the minutes are not actually unlimited, however if your family consists of normal/typical Americans, it's very unlikely that they would all talk enough to use up the minutes that come with the plan. I talked for hours nearly every day, as did my brother, and we never hit the limit. Also, mobile-to-mobile AT+T minutes don't count against your balance, which would typically include a lot of people who you would be calling anyways.
I've traveled through a LOT of countries in the past couple of years, and for someone who actually likes to TALK on the phone, few places beat the USA pricewise. Many countries, like Australia or Japan, do not offer many "talking" minutes. Prepaid 3G internet via USB stick was surprisingly cheap in NZ and Australia, but voice calls were not. The locals told me they usually only SMS each other since they can't make many calls without paying loads. Japan is similar with messages being used because calls are prohibitively expensive. In Los Angeles, people talk for hours every day while sitting in traffic just to entertain themselves, and they don't have to pay much for it. When I returned to LA from my travels, I added myself to my family's plan for only $15 extra a month, and did not get locked into a contract. $15 a month for virtually unlimited calling and no contract, using my a phone I already owned (a free phone from AT+T would have required a contract). Even without a family plan to mooch off of, prices for plans with massive amounts of talking minutes but additional fees for data or texts are still quite cheap. If you can call instead of text, good luck finding service with that many talking minutes at that price in many other countries.
Almost every country screws you in one way or another on your cell phone communications. In the US, it's tethering fees, expensive data plans, trying to lock you into contracts, and outrageous per-msg fees for sending or receiving(!) texts unless you also pay an outrageous additional $15 per month for unlimited texts. In many countries it's expensive talk times that prohibit your ability to have long unimportant conversations with your friends. At least there's Skype for jailbroken data users :) My cell phone and plan options here in Japan super-suck and I really wish I were getting a US type of plan. On the bright side, having email in your cell phones without a data plan is quite nice though.
One last point of interest. Those "free phones" from AT+T in the US can actually make money for you! I know a guy who would unlock/jailbreak his free iPhone from AT+T, then as soon as he's eligible to upgrade to a new model (for free or heavily discounted) and renew his contract with AT+T, he would sell the unlocked/jailbroken phone on Ebay for a lot of money. Repeating this every year or however often they offer it ends up getting him an awful lot of money back on what he's paying them.