Personally Windows 2000 was the only Microsoft operating system I’ve ever liked. And I’m including Microsoft Basic in that scope as well.
XP did mature into something that was decent, but the initial release of XP was just an uglier and more system hungry version of 2000. And thus XP drive me to run Linux as my primary OS.
But back when 2000 was around, most other OSs were terrible. Linux was getting close but still had a lot of rough edges. BeOS was awesome but you could tell it was a dying company. Apple were struggling too: MacOS 9 was less stable than Windows 9x (and that’s saying something!) and OS X took a couple of releases to really take off. Atari were dead. Amiga was basically only ram by enthusiasts. Yet Windows 2000 arrived and it felt genuinely like a next generation OS for its time.
Windows 2000 took NT4 and focused on bettering the stuff that didn’t work rather than breaking the stuff that did. Often little changes like adding short cut keys to Notepad.exe. Whereas every version of Windows since has done far too much GUI overhaul (and always to the detriment of UX in my personal opinion) while doing very little to improve my core complaints with the OS.
I get this is going to be my subjective opinion, just like Windows 7 is yours. But I did wasn’t to share a counterpoint to the praise of Windows 7.