I've never owned a Windows machine, or a Mac. It's not that I'm particularly hardcore about open source, it's just that I got used to a command line back in the old VIC-20/DOS/DesqView days and never really got away from it. Our undergrad computer network was very convenient, but made up of about four flavours of UNIX, and in fact they had a load-distributing program at login that meant your initial login was not just to a random machine but to a random UNIX flavour. Somehow the IT folks made this work tolerably well. After a few years of that, when I finally got a home computer, I chose to run Linux on it.
3 hours ago