You speak in the past tense? We have clients still running Windows 2000, 2000 Server and XP Pro, they would upgrade except for the "Domino effect".

If you upgrade from any of the above you then get caught up in a full site upgrade of OS, server OS, Hardware, and business applications, not to mention network hardware, security and backup systems, printers and firewalls.
What starts as a single machine upgrade often turns into a big site upgrade project with substantial consultancy and support costs.

Don't get me wrong, this is how we make a living so we should love it, the problem is that since the recession buzz words like ROI may be dead but common sense has returned, our clients rightly ask Why they actually need to upgrade? and in a lot of cases if systems are performing well they don't.

Windows 8 will take root in the retail market because of OEM licensing deals with Microsoft but I can't see any honest IT consultants recommending it to businesses in it's current buggy state!