to be fair:...
MS Dos, there are at least 6 different versions of this.
Windows 3 and three different versions of this (3, 3.1, 3.11)
Windows 95 (two versions of this) (a and b)
Windows 98 (and two versions of this) (first edition was pretty crappy, second edition was the one that was ok).
Windows ME (was seemingly only released to trry and get a tiny bit more money from the original DOS system, thus still suffered from all the problems of dos based systems, and because it was new, lacked driver support, and since it was surpassed by windows 2000 never really got driver support proper)
Windows NT (was released as two versions 3, and 4.5 -4.5 still holds the record for most service packs (6)), this wasn't a home os, and those that tried to flit between windows 98 and windows NT had to learn where everything was twice. it was a very good OS. powerful stable etc, but wasn't much loved due to the fact that it was around when the whole world was using 98, and it was different to 98.
Windows 2000 (was named wrong, it should have been called nt5, it was called windows 2000 as a excercise in pyscology, people didn't want to buy nt in the shops so it was simply rebranded and people bought it, (loosing support for some joysticks, midi controllers etc, basically anything that wanted to talk to hardware directly instead of through level 0 dll files) -which is why that OS had a bad rep.
Windows XP is possibly one of the best windows os's ever, the only problem with it is how bloated it's gotten after service pack 3.
Windows Vista was a mistake, I understand that the OS dev team had to show something for their efforts (massive gap between xp and vista), but the release schedule was a big mistake, everything that was going to be great about vista, (new security new file systems new features etc), were mostly dropped to make the release.
Windows 7 is what windows vista should have been, and if it weren't for vista windows 7 would seem even better.
To be honest, I voted for ME, it was an os that should have never been, (but Vista is pretty much level with it).