Most games are still Windows/OSX, with a few notable exceptions (e.g., House of Neuwirth, Steam). In regards productivity software, there's no commonly used Windows package that doesn't have its equivalent--or superior--in Linux. So, if you wish to make the assertion that you'll continue to use Windows because of the games, that's fine. That's what I use it for (that and Netflix are all I use it for). Given the price difference between the Linux software packages (which are almost always free) and the Windows software packages, unless you wish to pirate all of your software, a fully equipped Linux productivity desktop will be easily a thousand or two fewer US dollars less than an equivalent Windows desktop.
So, explain to me again why I should buy Windows (and its software), when I can have an equally powerful, equally fast, and manifestly more secure OS/software setup for free?
Finally, there are some instances where Linux is clearly superior to Windows, e.g., CGI, 3D modeling of molecules, etc. Avatar, X-Men, et al., are product of a super-cluster comprised of over 4,000 HP blades, containing 104 TB of RAM...and running on Linux.
In part, this is due to Linux's OSS background, which allows programmers to modify existing programs to their purposes. It's also undoubtedly due in part to financial reasons. The cost of clustering 4k blades under Windows would be...insanely prohibitive.