@Ted Treen, @Richard 102
OK, while your comment that lots of people still use Win 2000 is true (I probably should have added Win2000 to my list of Vista and XP) your statement that,"Macs [...] need so much less support" is complete nonsense. It's almost never the OS that needs support (be it Windows, OSX or Linux). It's almost always the user. For example, have you ever watched an average office worker try to use a MacBook for the first time? Within 5 minutes, they give you a litany of questions like "Where's the delete key?", "How do I right-click?" "Why won't my [software of choice] install on this?" The fact is, most people, and most businesses, are used to Windows. The support cost of migrating to OSX (and answering all these questions) would be massive. So they don't do it.
Secondly, you appear to be suggesting that using Macs would reduce the IT dept's workload, and that the IT manager doesn't want this for some reason... do you actually know and IT managers? If presented with the option, they always take the option that is likely to generate the least future admin work for themselves. The fact that they almost all pick Windows over OSX should tell you something.
My gripe is not so much with Apple itself - as you point out, they have a pretty decent product for the market it's aimed at. My gripe is with fanboi reporters who over-hype Apple's products unnecessarily, and give their press releases more importance than they really have, without any justification.
And people copy Microsoft more than you'd think. For example, OpenOffice copies loads of concepts from Word and Excel (don't get me wrong - I'm not calling OpenOffice itself a copy - it isn't - but it does copy some of the better concepts). Also, Palm famously tried to "do a Microsoft" by splitting their hardware and OS businesses... and look how that turned out... By the way, if you believe the fanboi rumour sites, Apple are bringing out a tablet computer - now who's done that before? Surely not the Windows OEMs?