If you are content with your Windows XP machine, you might see no reason at all to buy a new computer this Christmas, possibly because most of the new PCs and laptops on retail shelves run Vista. And Vista by itself seems not to be a compelling reason to buy a PC.

Security no longer seems to be an issue; people simply don’t believe that Vista is that much more secure. Corporate customers looking for benefits in managing PCs over networks and connecting mobile devices see only incremental improvements in Vista — not enough to drive businesses to upgrade. Most businesses have worked with Windows XP long enough to develop their own tried-and-true manageability and mobility solutions and best practices, so why bother. And yet, many corporate customers are signing Vista licensing agreements without doing the upgrade yet, future-proofing their businesses for future Vista upgrades, and this helped Microsoft project a glossy revenue report.

And so the Microsoft inertia continues, despite evidence that Windows and Office vulnerabilities are off the charts this year. Apparently it’s still extremely lucrative to exploit vulnerabilities, especially those in Excel and Word. The older Windows XP with Service Pack 3 offers about twice the performance of the new Vista, according to recent benchmarks. And it is possible to cut down on the bloat in Windows XP that leaves it so vulnerable by turning off services you don’t use.

So what will change the landscape and make it possible for larger numbers of users, especially corporate users, to overcome Microsoft inertia? Here are the leads I’m tracking:

1. Software delivered as a service will help corporate customers break the Microsoft operating system habit. Successful service operators like Salesforce.com (now Force.com) and NetSuite are changing the business landscape. Web applications like Zoho and Google Apps are helping small businesses and consumers break the Office habit.

2. Apple will continually expand its alternative installed base of machines running OS X, and may soon make a huge marketing splash about running Windows XP applications on Macs.

This is not so far-fetched. Apple developers suspect that Mac OS X Leopard contains at least the building blocks for Apple to one day add a compatibility layer for running Windows apps right alongside Mac OS X apps — without Windows. I think Robert X. Cringely had it almost right back in April, 2006, when he wrote that Apple would offer the ability to run native Windows XP apps not by using compatibility middleware like Wine, but rather by implementing the Windows API directly in OS X. That didn’t happen in the current version of Leopard, but it could happen in the near future. Cringely wrote back then:

I’m told Apple has long had this running in the Cupertino lab — Intel Macs running OS X while mixing Apple and XP applications. This is not a guess or a rumor, this something that has been demonstrated and observed by people who have since reported to me.

Could it be the best of both worlds? Corporate users would be able to transfer existing XP licenses and applications they own. No need for emulation that would be vulnerable to Microsoft meddling.

3. Smartphones are growing in popularity as productivity devices, and the drivers are Google with its Android smartphone software platform, and Apple with its iPhone. Lacking a innovative, dynamic and easy-to-use interface to mobile devices, Microsoft Windows is weak even with the proliferation of Windows-based phones. There is no compelling reason to use a Windows-based smartphone, as the applications that tie corporations to Windows don’t run so well on them.

4. Linux will grow exponentially, especially in overseas markets. You can now order a Dell Inspiron 6400 notebook or Inspiron 530N desktop and have Ubuntu 7.04 pre-installed as an option in the U.K., France, Germany, and the U.S. General reports indicate that laptops normally work out to about $50 cheaper compared to Dell’s “Home” versions running Vista.

Linux also has a major push coming from the XO Laptop, billed as the best Linux laptop ever made, from the One Laptop Per Child (OLPC) Project, which will soon be available to Americans, as long as you buy two for $399 and allow one of them to be donated to a child in the developing world. The XO laptop is based around an AMD Geode LX-700 CPU. It also has a 7.5-inch LCD display, two USB ports, an SD memory card slot and Wi-Fi, and is encased in a “hard” case with built-in carry handle.