Windows 8
Like the first entry said other versions were a hit except Vista. My opinion about windows 8 is that when windows 3.1 came out, it did change the world, no more DOS and black and blue letters screens, it was a wonderfull window with "colors"; now Windows 8 will also change the world by almost forcing most of the manufactures to make screens with touch in them. The metro style design in my opinion is a excellent choice, the OS is fast and graphs are better even if you have a poor graphics card. In summary I think Windows 8 is another big hit.