What OS do you use?

I use Windows 10 64-bit, Im thinking of changing my 2nd PC to Linux Ubuntu or CentOS for management of files and make it easier to get stuff and manage it. But what do you run?

Windows 7 32 bits I only have that because I do not have any more PC.

For servers i prefer debian 9, for users i prefer windows 10. I actually use WIN 10 x64

I use Windows 10 64-bit, and on my other pc i have ubuntu server 18.04

I useWindows, but sometimes also open source Operating Systems, like Linux...
I have never tried macOS...

i use windows 10 64bit build : 17134
Familly
but linux is cool also , and all variant like kali linux

Windows 10, Windows 7, and some linux flavors like CentOS and Ubuntu based OS (mint and OSGeo)
oh and also windows servers

Windows 10 + Arch Linux dual booted. Arch is what i use when im not gaming.

I familiarize myself with as many as I can, exept mac OS, as its too expensive