It does not sound to me like a good idea because such boycotts would target primarily the "good US-ers," academics, symbol manipulators, assorted do gooders, tourist industry etc. - which although goofy are still a force for good vis a vis the forces of evil led by the Kenneth Lays, Dick Cheyneys, and assorted captains of weapons and oil industries. And these evil industries do not produce goods that can be easily boycotted - unless you want to turn your power and heat off altogether. Oftentimes, US corporations buy offshore companies so most people do not even know that US corporate imperialism is already in their country, pulling the strings of their friendly "local" corporations. Moreover, how are you going to boycott the manufacturers of cruise missiles or F-16 fighter jets, since the public has zero say in purchasing decisions of these gadgets.
Another question - how can "good" US-sers boycott the US? I am trying my best, e.g. by not buying a car and using public transit instead on the assumption that cars are the only genuine product of the US corporate industry available to the public (you would not want to boycott US family or organic farmers, would you?), but such a boycott is not possible on any larger scale, because there is no public transportation in the US outside a few big cities.
A better idea may be a borrower's strike - kicking capitalists in their financial balls by maxing out your credit cards, and then going Chapter 7. It is legal, it is fun, and it is easy to do - an "American Express dream" of a sort. And the added bonus is that it would divert tax dollars from weapons programs to indirect support of people's spending sprees, as the Fed, no doubt, would bail out the failing credit cards companies and banks.
Wojtek