3.1- Lots of fun
95 - The blue screen of death becomes a meme
95v.c - we are introduced to USB devices and the most stable version of the OS
98 - no real improvements over 95v.c, I had to restore this one several times
Windows me- sucked. It was the vista of its generation and really shed light on why we needed the nt kernel.
2k - the epitome in the Windows line, nothing has been better before or since
xp - for everybody that never heard of 2k. Introduced a stable, standard gaming platform. Introduced the Barney's playhouse gui.
Vista - I was one of the early adopters, and it had so many hardware compatibility issues as well as gaming crashes. I reverted to xp. I still have an extra copy of xp that I purchased around here just in case I need a gaming computer up and running fast.
Windows 7 - some peculiarities with multiprocessing, but you get benefits also. I noticed that some of my old software does not run as well. Overall, stable, and a worthy successor to xp with the upgraded DirectX. Unfortunately, I think we would all still be on xp if it supported the latest gaming. Windows 7 didn't actually make anything easier, more pleasant, easier to find, so on and so forth… It's just different. And that's probably going to be the case for Windows 8.
As a side note, Linux is a lot of fun except in the following scenarios:
gaming compatibility
occasionally hardware compatibility
If you could fix those two things and make it standard, you would have a winner. Unfortunately, that community has no interest in standards because they value their independence over functionality. A real shame, and it will probably be second banana until they decide to pool their resources into creating a true platform.