Windows 7 is my favorite MS OS so far. In its last few days, there were still some very odd issues with WinXP that never got sorted.
Major Windows versions are like star wars movies - not every one is good
- Windows 3.1 - the first decent version of Windows, early networking, Win32 API's, some early DirectX
- Win98 Second Edition - everything Win95/98 promised to be, but it took SE to deliver on those bets
- NT 3.5.1 - one of the most stable versions of windows ever... trivia, it ran native OS2 apps as well
- Win2K - awesome sauce
- WinXP - like Win2K but better
- Win7 - like XP but even better... with the right version - my pref was Win7Pro
- Win10 - outside of the privacy concerns, it's actually not that bad...
Versions that were less than awesome - the Jar Jar Binks of Software/Operating Systems...
- Win3.0 - nice ideas, but dosshell underneath...
- Win95 - nice start, but ugly underneath, same with Win98 non-SE
- Windows Millenium - remember that?
- WinNT 4.0 - NT meets win 95 in a dark place... and this was the love child
- WinXP Pro 64 bit edition - I actually had this on a opteron workstation back in the day, and it was painful - WinXP without the joy...
- Windows Vista - less said about that, the better...
- Win8/8.1 - outside of MetroUI, it wasn't that bad, but OMG, MetroUI
Win Server versions - my thoughts there are similar to the Windows Core versions mentioned above...
WinCE - mixed feelings there - ARM/MIPS/x86/SuperSH/others - it's a weird place, but it's more common than most folks would acknowledge... my 2012 acura runs WinCE for the in vehicle stuff - I think Ford's Sync stuff was similar on the first pass..
And then there's WinRT - nice effort... not very successful - nor were WinNT on anything but Intel (WinNT used to support MIPS/PowerPC, and DEC Alpha back in the WinNT 3.5/4.0 days)
I was always puzzled about Windows Phone on ARM - why didn't Microsoft and Intel join forces there - Intel was (and still is) Android, where it doesn't do well compared to ARM... An Intel based Lumia handset would have been really nice - I've played around with Win8.1/Win10 on a low end tablet (HP Stream 7), and it's not that bad...
The most obscure version of Windows -
Windows Fundamentals for Legacy PC's - it was a cut-down WinXP system for Win95 era PC's - one had to be part of the secret society perhaps, as one couldn't get this publically, but it was there - mostly for thin clients, and eventually was replaced by Windows for Thin PC's - which was based on the Win7 core.
I'm told there's over 50 million lines of code in the Windows core OS - and that's not counting the .NET frameworks...
When one considers that - Microsoft has done an amazing job with Windows and trying to keep it secure...