We need more options.
There are plenty of options out there that are not given a spot on this poll.

I actually have fond memories of windows ME it was the first time I had my own PC. Circa 2001 ish

After that all windows are decent, really loved Xp

I still encountered some serious bugs with Windows 10 (both me and my gf), so I definitely can't say it's the best.
The best for me was Windows 8.1, followed closely by Windows 7

I prefer Ubuntu. Windows is a bit slow and pretty unreliable, its performance degrades over time. The update system that demands multiple reboots looks massively stupid. I would say that Windows is probably what drives me off PC gaming. So I use my PC for programming, web browsing, light video/image editing and leave my game to consoles. Of course, I understand if someone uses Windows because he likes it (matter of preference) or if he needs software that's Windows-only.

I really like OS X, but the low C/B of Apple's laptops usually drives me away. I love their build quality, but when you can buy two regular laptops with better specs for that price, quality becomes a moot point since you can change hardware more frequently. So I rather buy a powerful laptop and put Ubuntu on it. I've used other Linux distros before, but settled with Ubuntu since 2008.

A car it's just a mean to get to places you want/have to be. It's still reasonable to ask which brand/model people prefer. Even if we talk about your bus example, in cases where you have more than one company or option of public transportation, it's reasonable to prefer one because it's cheaper or it has better quality.

Win 3.1 still sounds best in that respect, such a classic:

That doesn't make it modern though.
XP had an elongated life span anyway thanks to the disaster that was Vista, that OS was archaic before support ended.

Windows 7 is the modern XP

It was succeeded in a similar fashion by Win8. 

Win10 has heralded in a new era of user resistance. It will be some time before a full reluctant transition to the OS is complete, and only then will the true vision for Win10 be realised.

By that time I'll be running legacy software on my Win7 machine, or will switch to Linux if need be. 

XP and 8.1 for me

I'm quite surprised at how many users voted for a Linux (the distinction between "Linux" and "Ubuntu" is ridiculous): Currently over 20%, more than twice as much as for MacOS.

Does vgchartz really have such a a large number of Linux users? Fascinating.