For me, I use a combination of Windows and Linux. Both have their advantages and disadvantages.
As IT support at work, the worst two I've encountered were ME and Vista. Windows 7 is currently too new to really comment on, but so far I haven't encountered anyone with an issue with it and I've also been using it on my home PC since its launch. Vista has plagued me with OS crashes (mostly caused by Windows updates) and I've lost count of how many computers with Vista (various brands, including Dell, HP, etc.) I've had to repair or reinstall the OS on, where the crash was not caused by HDD failure. Resource and disk usage were another thing I didn't like about Vista, although if you had had plenty of RAM, a fast disk (or SSD) and no OS crash, then you were one of the lucky ones to escape and probably wonder what all the fuss was about.
For Linux, I mainly use it for rescue operations, such as recovering data from failed hard disks. At work, our website is hosted on a Linux server, as there is plenty of PHP based packages and plug-ins freely available. Even if you claim to have no interest, let's not forget that this very website is running on Linux servers.
It was bad enough Microsoft finding reasons to get people to switch to Vista, considering there was more stuff that actually worked in XP than Vista. Windows 7 in my opinion is more of a bug fix for Vista, e.g. rather than release a service pack, Microsoft figured it could make a quick buck selling a new OS and sure enough Windows 7 was a success. Now, let's see how well Microsoft can convince people to make the switch to Windows 8 once it launches.