This is my list of windows versions that I rank by my opinion of their usability and abilities "of their time". That is, not ranked by comparing them to current standards, but comparing them purely by how they operated in their hayday. This is purely my opinion, and you will most likely disagree with it.
Personally I don't have much respect for Windows, but it did have a few highlights during its time. So here goes. I award the number one spot to: