I spend 99% of my time on Ubuntu, but still keep a stray Windows OS around for Dota/Warzone. This last year I've only clocked 4 hours granted... but It'd be nice to actually not care anymore.
It's really weird, one of the things as a kid I remember losing my main WIndows install being a big deal.. days or recovery. Now I just sit down at a Windows machine and it I don't care what's on it. I don't use windows for anything but the odd game.