For everything but VR, Arch Linux with KDE Plasma. For VR, Windows 10
I've played VR on Linux before with my Vive but it's definitely not feature complete yet. I just got Knuckles for it though so I've been using the Vive with them a lot recently, so I might start trying it more often. The lack of desktop view in SteamVR on Linux is really annoying though (I got it to work once, but that was the only thing that worked at the time lol)