Comment Zorin (Score 1) 448
http://zorin-os.com/Zorin-OS is an Ubuntu derivative design precisely for this purpose.
Personally I think presenting users with a mock-up of Windows that isn't Windows is counter-productive because IMHO Windows' desktop environment is continually flawed and year's behind the current crop of open desktop environments.
Personally I prefer to show those who are interested the popular DE's such as Gnome3, Cinnamon, Unity & (less so) KDE in their unaltered glory as these show really how backward the whole 'Windows way' is nowadays.