I kinda think they hit the sweet spot with Windows 2000. Not as bloated as XP, not as user-hostile as NT. I was never more comfortable than when fixing my old Windows 2K boxen.

XP's okay, but they did a lot of UI jiggery that still feels counter-intuitive to the lemur. Vista scares the daylights out of me. Windows Genuine Advantage is the mark of the beast -- you heard it here first.