Windows 95 (crap)
Windows 98 (good)
Windows ME (crap)
Windows XP (good)
Windows Vista (crap)
Windows 7 (good)
Windows 8 (crap)
Let's just wait and see what the EU commission has to say about this. I call another multi billion euro fine :)
I agree though that the EU might be interested in something like this, but it wouldn't be Microsoft they go after but the OEMs to force them to allow users to install their own keys or at least turn off the signature validation.
Also, Vista wasn't crap. Microsoft lowered the system requirements to appease intel and their OEMs. So no surprise it runs like crap on a 4 year old laptop. 2 years later when 7 came out everyone had 2 year newer laptops 7 looks great.
You can see the same with with corporate IT departments: many of them decided not to upgrade to Vista. Why bother when Vista has marginal improvements with lots of bugs? Instead they stuck with the rock solid XP and waited until Microsoft (and the vendors) fixed things (Win7).
I expect corporate IT will view Windows 8 the same way: Metro is a big headache they'll want to avoid. They aren't going to be deploying Metro apps (at least not at first) and they'd probably disable Metro to avoid confusing users. If Microsoft is hoping to make Win8 the corporate standard, they'll have to do it via tablets. Presumably if everyone is using Win8 tablets, they'll eventually want Win8 on their desktop/laptop. Otherwise, I'd expect many IT departs to skip 8 and wait for 9.
I still stand by my list.
98SE is missing, but I don't really count a second edition of one operating system to be a new operating system, though that might also go for ME.
Windows 2000 and NT4 are not here, because they are enterprise software (anyone here tried playing games on Windows 2000, most of the games I tried in my childhood did not even install on 2000).
I have also left out Windows CE. Which is utter crap. HP even put a dedicated reset button on the front of their devices running CE 2.x because it was used so often. It became very popular though and is still used in many gps units. Mind you though, Windows Phone was based on CE until version 7. They were popular with the enterprise because of exchange sync and the general support in windows. Everyone else used blackberries and palms and now of course iphones and androids.
I have also left out Windows Server editions. Though these have mostly been rather good because you didn't need a college graduate to install and configure them, though many were just as slow and buggy as their client counterparts.
Also, maybe I'm remembering wrong, but Windows 98 was just like Windows 98 SP1, no? If that's the case, why aren't you arguing for all of the service packs on WinNT, WinXP, WinVista, etc.