I've been to Amsterdam once, and quite frankly could not possibly care less about the coffeeshops or doing drugs. I am aware that, as a student, I'm part of a minority who doesn't see the appeal of doing drugs.
but anyway, while I was in Amsterdam (about 2 years ago now), I came across the occasional coffeeshop, but I did not find that disturbing at all.
That said, I agree with what was said about the drug tourists usually either staying in a cheap hotel/hostel rather than the more upmarket places. I've actually found most drug tourists (from within Europe) just come by car (usually a cheap old French car, like a Peugeot 105) and also take a generous supply home.