DEFINING THE QUESTION
I think Americanisation refers specifically to cultural homogenization, NOT to political/military/economic dominance. To what extent are other countries' cultures becoming like the USA? (And how much do non-United Statesians in the two continents of North and South America hate the use/misuse of the word "American"?)
WHERE WE ARE NOW
To a great extent, Americanisation in the West is over with, i.e. it has been accomplished. You probably aren't aware of this, but talk to your grandparents and they'll tell you how American expressions and fashions flooded the country, undermining the "Australian-ness", "English-ness", whatever-ness of their culture. But now no-one complains about all the McDonalds's etc, because they've grown up with them. (On the other hand, try-hard "homeboys" in Australia are a more recent annoyance.)
HISTORY
This is perfectly understandable. Throughout history, the dominant country has influenced its neighbours, partly through trading power (TV shows, music, food products, etc, abundant and cheap), partly because it's natural to emulate someone richer and more powerful than oneself. Before the rise of the US, Britain was the dominant power, and British culture permeated the world.
(Check out the Wikipedia for "Lingua franca" for the way the international language of choice changed throughout history, eventually arriving at English.)
CULTURE FLOWS BOTH WAYS
But it goes both ways. There may be McDonalds in China, but how many Chinese restaurants are there in the US? (Answer: lots) There are also lots of Indian restaurants, Swedish furniture shops, and (God help us) Irish theme pubs. Unless the US puts up a new Iron Curtain, culture is going to flow both ways. Culture naturally flows FROM wealth, which can afford to spread it, but culture also flows TO wealth, because wealth can afford to buy it. (Witness the recent international interest in the death of Steve Irwin, a living stereotype of "Australian-ness".)
SHOULD WE STOP "AMERICANISATION"?
So the answer to your original question has to be "no", unless precious local customs are being driven into extinction by a fad for the new cool thing. But then, cultures change anyway. Can we freeze time or stop languages from changing? Should we isolate "exotic" societies in some kind of cultural zoo? Think about that while you chew on your Hamburger (German) and nibble at your French fries.
MARKETING TO YOUR TARGET'S SELF-IDENTITY
How does this tie in to marketing? *shrug* I'm not a marketeer, but in terms of appealing to particular market segments, Americanisation and attitudes towards it are factors that can be important. You could market something as "cool (dominant)" if it partakes of US popular culture (blockbuster movies, Coke), or "cool (exotic)" if it doesn't (French champagne, European beer *waves at Beer thread*). You can change your pitch depending on how your target market feels about US pop culture.
Of course, "America", in marketing terms, is an image, not a geographic location or form of government. E.g. plenty of "anti-American" people seem to have clubbed together to make Michael Moore a very rich American. (The same applies to things like art-house movies and indie rock.) On the other hand, I suspect most American-style jukeboxes are now made in Asia.
In non-US markets, you can appeal to patriotism (even if the product is made/designed elsewhere). On the other hand, you can also make use of what Australians call "cultural cringe", i.e. the feeling of non-Americans that their cultural icons are crude, inferior or irrelevant. (Plenty of Australians like Vegemite, for instance, but some of them find the patriotic associations embarassing.) (Leaving aside the US for a moment, you can also use an "exotic" image, or even an "international" image (e.g. Microsoft's advertising). )
CONCLUSION
So: the US is culturally dominant (which is perfectly natural), but also influenced by other cultures (ditto). The US and the West as a whole is becoming more culturally mixed, leading to a market in which a product has a wide choice of cultural "identities" to choose from. The value of "America" as an identity depends on the self-identification of the consumer segment you are looking at.