I liked 7. 8.1 was a good one too. We kept that even after 10 was implemented. I have gotten used to it but I'd go back to 8 in a heartbeat. Plus, we like playing Hidden Objects games via CDs. They are not compatible with this newer version anymore & doesn't look like they are making newer games.
For me Windows 10 is stable and worked out well on most of the scenarios. Some of the stable options with the Windows are pretty good too. It is going to be pretty strong on the usage level for few more years before we move. I am doing most of the design and dev work on Windows 10.
Generally, I believe they Windows 7 is one of the best windows version that's ever been developed but since the release of Windows 11, I have been drifting close towards windows 11. It's going to take a while but my preference shifts completely to Windows 11.
Windows XP and Windows 7 are IMO the best versions of Windows. XP was super stable and came with many new features, Windows 7 was a breath of fresh air after Windows Vista. I used to have a Windows Vista laptop and it was annoying to use. I had issues with programs not working, and the laptop itself overheated. :V
I'm still messing with 11 on two computers and like it, they have lifted many of the CPU restrictions on it now so many with a computer 5 years old can update, I updated my old PC a few days ago, only took like 10 minutes.