Firstly, I'm Canadian, and you have to remember, we base a lot of our national identity on the idea of NOT being American, so if there's any anti-American bias in the way I think, it's probably that. I usually would say 'I don't like the US', but that's purely on the grounds of belonging to the country I do. Reasonably, I understand why the US is what they are, and can't exactly fault them for that. In the end, I like making fun of America for its failings, but, hey, I can take the reverse stereotypes, eh?
So, on fairer ground, no, the US is no evil nation, any more than any other is. There are very few I think that history could classify as outright evil. Maybe the Assyrians, and their ever-present war-mongering and brutality in the name of Ashur, but those that go to such harsh extremes have been few. Even the Aztecs, renowned for their mass-sacrifices, had only begun that in the hundred years before their destruction - a sort of fanatasism had overtaken their religion. Anyway, back to the US. Certainly, they've acted questionably. They've only entered the greater wars when it's served their own interests. They've removed democratically elected communists, and replaced them with dictators of their choosing. They support men like Saddam Hussein, then turn on him when the climate changes. Further back, they warred in the name of Manifest Destiny. But can that truly be looked at too harshly? I'm not being cynical, but it's to be expected. That's how any empire behaves, and those at the top must before all else look after their own self interests. Moreover, as has already been said, the country itself, because of that position, stands under far greater scrutiny. In the end, however, I'd say that American is a better empire than was Britain, or even Rome.
Actually, if there is any country or empire I'd liken the US to its Athens, circa 460BC. At that point they had within the generation driven off the great, supposedly tyrant and oppressive, power of Persia and her proud kings, being along with Sparta the two main factors in bringing Greek freedom to be. Typically, Sparta was the stronger. Yet due to her navy, and her increased power in the Delian league, she became increasingly imperial and expansive in her actions. Through this time, a typical cry was that they still fought for the sake of 'freedom' and 'democracy'. Eventually, though, certain foreign policies against those who would not be on her side (a sort of 'if you're not for us you're against us' mentality) led to an appeal to Sparta by the island of... Thassos I think it was. Anyway, this precipitated all-out war, which resolved nothing, really. Eventually, however, things became worse. A second war began, at first being led by the statesman Perikles, but by other when he died in its second year to plague. Athens still claimed to fight for 'democracy' and 'freedom', even though she had long ago become an empire to rival the Persians for tyranny, and her democracy voted in such atrocities as the destruction of Milos. It is the historical point against democracy, an example of how we must be wary of the tyranny when all are given power to rule. Anyway, that's the sort of path I think I see the US taking, that of Athens. Right now, they're probably sitting at about the 460BC mark, maybe a bit later. Time-wise, this is about right, too. If things keep going this way, in the next few decades another strong empire will challenge them (China?), aiding other countries complaining of their foreign policy. Finally, they will be defeated, only to have democracy return again better than before after a time of dictatorial chaos. I wonder if that won't be the fortune of the US, and if they are not the new Athens? But I really went out on speculation with that. The thing really is, you can't really call the US evil. Every country in their position would act at least the same, if not worse. That history has proven, with very, very few exceptions (case in point in Persia, that the Greeks saw as tyrannical and evil: they were amongst the most tolerant of empires to have ever existed.)
In the end, I know we won't ever have a perfect empire controlling the world. All we can hope for is the best and, well... I know those who are faced with the power of the US will disagree with me (as opposed to me who lives in a country that is allied), but the US is pretty good. Would Russia be better? China? Britain? Eventually power will fall to another country - that I'm sure about, because even the US is not immortal. Maybe this will even happen within our own lifetime, if one such as China comes to prominence. But until then... we can make fun of and declaim the US all we want - critisism is for the best - but amonst it we must remember that we're not realistically going to get all that much better. Not from a country that has to look after 350 million of its own people first and foremost.
By the way, an interesting point, but... one of the points at the beginning was the owning of guns. I have a friend who, though being essentially Canadian is still thinks of himself as an American, and is also a bit of a gun fanatic. Anyway, he's before told me that the countries where handgun restrictions have come into effect actually have more gun crime than other places. And it makes sense. Criminals get guns regardless, but if they think a civilian might be armed, it will make them think twice about something. Furthermore, I know that here in Canada our multi-billion dollar gun registry is an absolute failure. Owning guns has not led to any sort of decay in the US, I'm certain.