"I used to do 80 per cent of my work on the Windows PCs and 20 per cent on Linux, but now it's reversed," Gaskin says. "Now, it's really 90 per cent on the Linux system. On Linux, I have my Firefox browser and OpenOffice, and I can do all the things I normally do for most of my day, browsing, writing, presentations and spreadsheets. All for the price of zero. And that's pretty compelling.

He says that a plus for Linux is its openness. "I got Ubuntu Linux with OpenOffice about six months ago, when Microsoft's Office 2007 came out," he says, noting that Office 2007 uses new XML-based document extensions. "Those docx files were making a big problem because you couldn't read them with Office 2003, and suddenly, Office was incompatible with Office."

When a colleague sent him a Word file with the new docx extension, however, Ubuntu Linux had no problem working with it. "I couldn't open it on my XP with OpenOffice, but the Linux version of OpenOffice Ubuntu could read, open and convert those docx files. So Linux was ahead of Windows by far there."

But beyond consumers and small businesses, most experts don't see Microsoft losing too much operating system market share, at least in five years.

"Today, we live in a Windows world, and in 2013, we'll still be in a Windows world," Madden says. "I'm a Mac user personally, but corporate applications are run on Windows and that's just how it is."

Metro Health's House agrees. "I don't know if anyone will challenge Microsoft in the OS arena," he says. "From our healthcare point of view, all of our applications are written for Windows, so we don't think twice about running anything else."

One caveat is Microsoft's OS licensing policies on virtualization, says IDC's Rose. Currently, if enterprises wish to run Windows in a virtual PC environment, they need to buy into Microsoft's Software Assurance long-term licensing and pricing model.

"Software Assurance has about a 1 per cent penetration rate, so obviously, that's a pretty significant way to kind of squelch adoption of virtualization on the desktop," Rose says, noting that it may lead some enterprises to consider alternatives such as Linux on the desktop.

But more likely, he says, is that Microsoft will realize that virtualization is actually good for its market share. "From Microsoft's, and our perspective, desktop virtualization is a win-win because Microsoft doesn't lose any OS licenses," Rose says. "If anything, it's good for Microsoft because it will probably mean there will be more Windows footprints out there."

Collaboration in the cloud

That said, experts say that even five years down the road, Microsoft will continue to dominate in terms of desktop applications, like the ubiquitous Microsoft Office suite.

"I see Microsoft as dominant in five years, solely because inertia is the strongest physical force," Gaskin says. While other, more open desktop suites, like StarOffice and OpenOffice, will make inroads, Microsoft's lead will be too much to overcome, he says.

A big factor here is that it's still much harder for typical users to purchase Linux PCs outfitted with OpenOffice than it is Windows PC with Microsoft Office. "Linux still has some things they need to fix, mainly because the vast majority of people aren't going to work harder to get Linux and OpenOffice than they are to get Microsoft," Gaskin says. "So the onus is on Linux to make it easy to use and install."

Another alternative is to access office productivity applications over the Internet, using services like Google Apps. Once again, experts say the Google choice will work for some enterprises, but for the most part, it won't be able to handle the varied vertical market applications that today's Windows-based tools can.