I’m running Windows XP right now. By necessity, not choice. Previously I was in university in a multimedia program, where many programs only existed on Windows, so I had no choice in the matter. Now that I’m working, I am programming using Microsoft’s ASP.NET 2.0 in Visual Studio, so as far as I can tell my only other option is to use a Mac. Which would require I spend money on buying it to replace this nice Thinkpad I am given to use. Not only do I not have money to spend on a Mac (though if I was given no-strings-attached cash I sure would buy one), but I don’t really have that great of a desire to change to it professionally.
For personal use, I could just as well use a Linux distro, but it would require a lot of time and dedication towards learning and setting it up on my gear, and to be honest I really have no desire to go through with this. So I’ll stay on Windows XP (I might consider upgrading to Windows 7 but not if they kill all the promised features like they did with Vista) unless Microsoft decides to no longer support XP, which I don’t see coming based on the worldwide usage rates.