I've been around computers since the Commodore 64 was still being sold.
I've played around with ms-dos, windows 3.1,95,98,xp,visa,7,and 8
Windows 7 is my OS of choice
I do own a Mac and it's got Mac OS Lion on it, but I usually only use it when I'm working on iPhone app development.
I've played around with some flavors of Linux but still mostly a novice at it in general.