In my opinion there is no other country with so much to offer the traveller as the US. All seasons, all climates, friendly people and amazing scenery, all in one package. Add to this the cheap dollar, and you should have millions of foreign visitors, happily spending their money over there.
This is where your image loss costs you.

Of course someone might say that you don't need us foreigners and our stinkin' Euros. That would be like a shopkeeper closing at noon, because he has had enough customers already. He is free to do so, but it is not good for business.

The tourist industry will stay, unlike manufacturing jobs that can be exported. You cannot ship the Grand Canyon to China. Also, your country already has the infrastructure, 
and skills, to serve a much larger number of tourists.

When travelling in your country I find Americans the nicest and most helpful people you will find anywhere. Your foreign policies, as of late, 
is another story, and the major source for your image loss abroad.
On a lesser scale, American television series does portray life in the US as violent, and might make people uneasy about visiting. My grandmother is worried when I travel to the US. Really!

Which TV shows are you thinking of that portray the US as "violent"? (I'm not arguing, just wondering which ones you have in mind!)

June,
well, we for example all the CSI:s, "24", "dexter", these spring to mind, when I was younger we had "Hill Street Blues" and other police series," Miami Vice", hee hee, nostalgia today. Not to blame any show in particular, just when you have lots of these, running
for years, when watched by people who have never been to the US, it does have an effect...