Takes deep breath... MacOS El Capitain on my MacBook, Ubuntu 12 on my study desktop, Raspbian on the, er, Raspberry, Ubuntu 12 house server, Windows 10 kids PC (x2!), Windows 7 wife's laptop, Ubuntu 12 in my workshop, Windows 7 wife's netbook - that's home done... Ubuntu 12 on my hobby VPS... at work - Windows 7 desktop and Ubuntu 12 desktop (4 screens), work VPS is Ubuntu 14 (I'll leave out the core servers I work on!)
Raspbian Jessie and Raspbian Wheezy on several Raspberry Pis, (about 6 total), used to have a desktop Ubuntu computer, but currently use a Windows 10 laptop. Then my brother also has a windows 10 laptop, and my mom uses a windows 8 laptop, and my oldest brother uses a mac.
Here: In my PC: Windows 7 Ultimate (x64) In my sister's laptop: Windows 10 Pro In my laptop (Sony): Windows 7 Home Premium (x64) In my netbook: Windows 7 Home Basic (x86)