Just Windows 10, I don't need to do anything fancy on it, it's good for gaming and coding, etc. It's pretty much just Windows 7 but a cleaner interface. Don't get confused with Windows 8.0, that version is horrible.
Had Windows 7 for awhile again, preferred it to 10 b/c these notifications suck dick. Would downgrade but meh, its whatever (windows.old is already deleted too lol).
Actually I've tryed all the OSs but now I'm using only linux along with windows, mostly linux, cause I love to run everything on it, I just sometimes switch to windows in order to use and create c# based checkers n programs.