I probably shouldn't have gotten political here - it's certainly off-topic. But since I did...
The United States is not alone in being a democracy, or being economically successful, having freedom (in general), or being militarily powerful. However, the U.S is unique in the extent of its intervention in other countries internal affairs.
Other countries have done so in the recent past - Britain was a world colonial power, but withdrew as its colonies' desire for independence grew. France, on the other hand, was a bit more belligerant, especially in Vietnam and Algeria. In Vietnam it did withdraw in the end, but they managed to put down revolts in Algeria.
Although they retained control of the government in Algeria, they faced terrorism that continued even after they pulled out of the country. It fell into political chaos, which many rebel groups still blamed on France - as a result, Algerian terrorists still target France. A few years ago, French agents foiled a hijacking attempt in which Algerian suicide hijackers had planned to crash an airplane into the middle of Paris.
The lesson being that intervention in the affairs of foreign nations makes one a target for terrorist groups within those nations.
That said, Osama bin Laden's stated goal really has nothing to do with the United States per se - He is from Saudi Arabia, a land where political oponents are imprisoned and tortured (and occasionally "disappeared"), and women aren't allowed to show their faces in public or drive cars. This is the regime that bin Laden opposes, and it's his stated aim to overthrow it.
It is also the regime that the U.S government supports militarily, through foreign aid, intelligence and technology. It is generally thought among opposition groups that this support by the U.S for the anti-democratic ruling royal family of Saudi Arabia is what allows them to stay in power, otherwise a revolution (or reform) would have occurred decades ago.
That being the case, the fight against the opression of the Saudi rulers is also a fight against the opression of the United States.
In their view. This is also the case in Palestine, Lebanon, Chile (though Chileans mostly concentrated on getting their country back from Pinochet), Iran, Vietnam (who were happy just getting rid of the invaders), Colombia, Philippines, Cambodia... the U.S government has made many enemies (to a large extent, with the ignorance or the American people themselves).
I should point out that ordinary people in those areas aren't particularly anti-American. They're quite happy with Nike and Coca-Cola and Hollywood movies and maybe individual Americans (if they think that Americans are as powerless over what their government does as those people are). But American foreign policy is not particularly progressive or well-aimed, and does as much damage as it does good.
The long term solution to security needs in general is to have no enemies. And since it's U.S foreign policy which seems to make enemies, that policy is what needs to be improved to reduce the incidence of terrorism against the U.S and improve security. Unfortunately, as of late the U.S government is moving in exactly the opposite direction.
Okay, back to topfree braless women frolicking on the beaches...