8
It functions the same way as windows 7, except so much smoother. Really fast boot times even on a regular hard drive and its really great to just press WinKey + S then type part of a program name, press enter and it opens.
E.g. Pressing WinKey + S then typing "Photo" will show a list of settings and programs involving "photo" and photoshop is the first in the list and highlighted, so I just press enter and it opens. By far my favourite feature of windows 8
Im sure that most people who will say "get windows 7" have never used windows 8 and are just circlejerking, it happens in pretty much every thread