Mighty, I've had similar experiences. None of my unix instructors were even aware that Mac OS X is Unix based, my Java lecturer went so far as to tell me I couldn't run Java on the Mac (when I know the Mac ships with a more complete and up-to-date Java runtime than any Windows machine) and my multimedia lecturer told me I wouldn't be able to use it for PowerPoint or QuickTime. And to think that these are the people who are teaching the world how to use computers, and are widely consulted for advice on software. Needless to say, I have set them right in each instance.
In the case of the networking lecturer who said I wouldn't be able to connect my iBook to the school network, I plugged into the wall and got a connection straight away. He scoffed at it. So I spent the next hour port-scanning the entire network and discovered root passwords for 5 of the universities servers, which I then showed him. Needless to say, he didn't appreciate this but he did learn never to tell me I couldn't do something.
Apple often seem to not quite hit the mark with their advertising. I've often said that the key to change is to start with the leaders. Consider the thinks-he-knows-everything-about-computers geeks with their overclocked boxes, or the programmers and web designers; these are the people who will be asked for an opinion on buying a computer. And Apple is not reaching these people much, if at all.
The answer is targeted advertising in industry journals. Java journals should have features showing Java programming on the Mac, and ditto for XML, Perl, PHP, and whatever else.
They should also be targeting the Unix/Linux crowd through Linux magazines. Adverts on the open-source and politico-computer sites like SlashDot, FreshMeat, OSDN, SourceForge et al would also go well, but these should be about drawing in a targeted market BEFORE telling them its a Mac, or they'll just dismiss it out of habit.
And most of all, Apple has to get back into the education market at the highest levels. How they'll achieve this, I can't even imagine.
Frankly, some of their advertising lately has been really wide of the mark.