"The USA" can mean either its government or its people. It is democratic, Constitutional, and oriented toward free markets. It has a very small Constitution, designed primarily to outline the structure of the highest levels of government and democracy in the country and the limitations of its power. The Constitution is respected as the supreme law of the land and is enforced strictly and interpreted carefully by the Supreme Court, which is made up of extremely knowledgeable people appointed by the President and Congress, but is largely immune from political pressure. The rules governing democracy are sometimes archaic and result in a lot of head-scratching from foreign observers and even many domestic voters, but there is a high resistance to changing the systems by which democracy operate.
The United States is the world's oldest surviving federation, which is part of why it can survive despite being so large -- many of the functions of government are not handled by the national government, or are only partially dealt with by it, with other important issues decided on a regional level by fifty different lower level States that have their own Constitutions and governments act like small countries, just without foreign policy (though they often have local military of sorts through the National Guard), and with restrictions preventing any particular State from taking actions that would be considered either oppressive towards its own people or overly disruptive to the economy or well-being of the rest of the country. The States are prohibited from negotiating independently with foreign countries or from enacting any sort of trade barriers, so that the States have a unified foreign policy and military stance through the Federal Government, and a high level of domestic stability and economic diversification.
The people of the United States are fairly religious, nationalistic, and (on the balance) tend to be more ideologically capitalist than those in Europe. Economic regulations are seen as suspicious and economically dangerous, while strong national patriotism and concern for freedom and liberty are considered to be very "American". The people regard the military as noble public servants, and generals and other military figures are extremely highly respected, though the usage of the military -- that is, the actions of civilian leadership over the military -- is not as enshrined, and the military is traditionally politically neutral, a practice which has been respected since the country's founding. Tolerance and free speech are highly held principles, but the extent of their application varies.
Due to a high level of religious freedom, and a prohibition on government interference in religious matters, the US is one of, if not the single most religiously diverse country in the entire world. Religious lobbies that use secular arguments to back their viewpoint are well respected, but purely religious arguments are frowned upon due to the principle of separation of church and state.
The political culture of the United States holds the government as a useful and necessary evil, but not to be trusted too far. Public television and radio are known and popular with a limited audience but are much weaker than in many other countries; government-funded media are considered highly suspect, as they are potential outlets for propaganda. The US private media corporations are among the most well-financed, independent, and diverse in the world. Private media corporations regularly broadcast public debates and interviews involving commentators, academics, and politicians of every color of political viewpoint, and frequently give voice to protests and criticism of the government. This all takes place without receiving threats of censorship from the government being criticized -- even hatred and prejudice are considered protected speech. Media bias is totally legal, but at the same time, the people of the United States expect an unbiased media. The interpretation of "unbiased" varies widely, depending on the viewer; the media is widely criticized by those who feel their viewpoints are underrepresented, and even journalists participate in the habitual introspection about whether the media is properly serving the public good. Many people see the media as an ally of the government against the public, while just as many or more see it as an ally of the public against the government.
Entertainment in the United States is a huge and extremely varied industry. It varies from lurid pornography to religious music and almost anything imaginable in between. (Dwarf Fortress, incidentally, comes from the United States.) In general, the broadcast media is fast paced, exciting, and inundated in advertising by private companies, nonprofit corporations, political causes. Reality TV and game shows handing out vast amounts of money to common people are very popular, as are sitcoms about seemingly normal people in everyday situations. Other popular themes vary from gruesome horror films to violent and heroic war stories to educational children's shows. The diversity of the US media has been a driving force behind an immense degree of "cultural imperialism", not driven by the government at all, as American media artifacts are exported to every corner of the globe.
Many people around the world find employment and are lifted from abject poverty by the manufacture of cheap trinkets or other consumer goods that the people of the US don't need and wouldn't miss, but buy anyway, much to the benefit of those making them. Others find the wealth of American investors to be the infusion needed to establish companies in impoverished places in the globe. The US government and its people donate immense amounts of money, food, and medicine to less well-off places around the world.
The United States is a country of tremendous wealth, knowledge, and power, supported by democratic traditions and domestic freedoms. Its military history is sometimes checkered, and other bad things have come from it, but these are reigned in by free criticism of the government and an intense desire by its people to be the "good guys" in the world, plus an easily inflamed public anti-government sentiment that the government does more to protect than to suppress. Public desire for a just government, freedom for its people, and a respect for human rights, in a federation where diverse States let you just move to pick your government through what part of the country you live in -- some have the death penalty, others ban it, some allow gays to marry, others ban it, some have great education systems, others give a lower tax burden -- all in all, the USA is a Pretty Good Country, where you can be what you want to be, the government doesn't breathe down your neck, and hard work and smarts are rewarded.
I know that a lot of people around the world and even in this thread think the current government of the USA is absolutely abhorrent, through its military policies and practices in Iraq and the War on Terror in particular. Luckily, the USA is a democracy that allows criticism of the government.
Today, a large majority of the people of the United States regret that the government decided to invade Iraq, and both of the two dominant political parties are on the verge of nominating candidates for the Presidency that have vehemently opposed what is widely seen as inhumane torture on the part of their government in the prosecution of the "War on Terror".
It's not been the brightest eight years of US history, but there's more to the USA than just its government. Even so, may the next four be better.
Edit: Grumble grumble "ubb code" bleh...
[ February 28, 2008: Message edited by: Jonathan S. Fox ]