Something like Windows 7 offers very little "overhead" more than a minimalistic linux distribution (say, something like Arch Linux) configured to be a modern desktop machine. I can't speak for OS X out of experience, but considering that in general, it's pretty close to windows, I'd say they're similar enough that it doesn't make too much difference. Furthermore, Windows and OS X both provide unique software solutions for video editing that Linux doesn't, often making linux a completely invalid choice for video editing.