I predict that in 10 years, open source software will be the dominant product line used by major corporations around the world. The reason I believe this is because the move by corporations to continue to cut cost, more specifically, IT cost, will draw corporations to use the open source model.  Today, Microsoft's licensing model is too demanding and expensive. Companies are forced to continue to upgrade their software and licensing agreement every time Microsoft upgrades its software. Let's say that a company was satisfied with Windows 95 and wanted to remain on this platform, they could not do so because anytime they wanted to add a new system to their network, they would have to install that new system with Microsoft's latest and greatest operating system, which is Windows XP today. So now, this company, who desires to cut cost is now forced spend more than they desired just to add a new employee to the corporate network.
   In comes open source. Now let's say that a customer has all of its users on a version of Linux using Novell’s Linux Desktop. They can add as many workstations to the network at minimal cost. They even get to use the latest distribution if they so desire. Microsoft cannot stand up to this change. It is somewhat poetic that Microsoft will fall victim to freeware. They won the browser battle by giving it away. They successfully shut down Netscape. Now their entire product line is under attack by freeware or almost freeware. As the quality of open source grows Microsoft will loose market share.
I do think that Microsoft will survive but they will loose billions per year over time. Now, don't get me wrong. I really love Microsoft's products. I especially like the .NET framework. This is a saving grace for Microsoft. I am just saying that there is a force at work that cannot be stopped. There are people out there who will write high quality code for free just because they enjoy the challenge. Then you have people out there who are coding high quality software for free just to bring down a major corporation's dominance.
Now that Open Office, Linux, FireFox, Jboss, Zope, Novell Evolution etc. exists, how appealing is it for a company to remain on Microsoft? The evidence is already out there. Microsoft is giving away its operating system to countries such as Germany and Taiwan. How long will American corporations sit by and pay top dollar for Microsoft's operating system when they are giving it away to others? The open source movement is a quiet storm that will affect many businesses.
Open Source also brings unprecedented opportunity for businesses that know how to take advantage of this trend.
Once companies like Novell improve on the installation and upgrade of their product line for the server and the desktop, companies like Microsoft will be scrambling to compete.
With all of Microsoft's wealth, they cannot beat the open source movement unless they can continue to encourage SCO to keep its law suit alive and put an end to Linux. The Linux operating system is the heart of this movement. Take down this operating system and this movement will die; at least until the community writes a new operating system to replace Linux. But, I seriously doubt that SCO has a leg to stand on. Bring this case to a jury and SCO will definitely loose.

One more thing. I also get to continue to code in .NET because or products like Mono. .NET is the best thing to happen to the developer community but because of Mono, even this may not help.