A touch screen is definitely not required for Windows 8.
I have been using Windows 8 for many months on one convertible tablet with a touch screen and one traditional desktop without a touch screen and I can efficiently navigate on each system. In my opinion, a touch screen does not make Windows 8 better. It adds more options.
In fact, for many operations, I find that the mouse and the keyboard can be faster than touch in Windows 8.
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