Microsoft OS releases are kinda like Star Trek movies - you always need to skip a release or two.
DOS 2.1. Solid and stable. Don't bother with anything subsequent until DOS 6.
Does anyone remember a version of Windows prior to 3.1? I sure don't.
NT 3.51 was my first acquaintance, but NT 4.0 was basically VMS with a GUI - that's what made it great.
95 was an achievement, providing a structure for development and basically automating hardware driver installation. Betting on its development was bold - even for a company the size and sway of Microsoft. Anyone who claims to appreciate open architecture should salute this as its genesis in the common market.
98 and ME? Meh.
2000, which essentially married the vision of 95 to the robustness of NT was where the bet paid off. I still love the 2000 suite.
XP SP2 was just dreadful. A firewall that just wouldn't work and blocked access to everything by default. Alternately, SP3 was so good MS had to support it until 2014 - an exceptional lifespan for a desktop OS. Hell, there's something like 1% of active computers STILL running it today.
Vista was a hog, no ifs, ands, or buts.
7 was great, 8 was "why?", and 10 has proven pretty darn good. Only installed 11 the other night, the jury's out.