Exclusively a GNU/Linux user, I used windows and MS-DOS for the longest time and never could grasp the concept of programming/coding or hacking at all. I had my days when windows slowed to a crawl because it depends on virtual memory (from windows 3.5 all the way to the current version, 6.3/windows 8!). I have a windows 95 (3.5 CD, 98 (4.0) CD somewhere, XP (5.1), 6.1 (7) and 8 (6.2) DVD too.
Only times I use them is: Grand theft auto (which killed the installation due to a stupid fuck-up), managing my Blackberry Bold 9900 (Java to the core), BlackBerry Q10 (QNX based).
I also happen to have NT 4 and 5 (2000) laying around, some DOS disks and 3.1 too.
Primary OS of choice? Linux Mint (*buntu based). Sorry, I wish I had some contributions. Where's DOS girl when you needed her...