First off, Windows 10 doesn't even exist. It's actually Windows 9, but they called it 10 because 8 sucked so bad that they had to skip a number to throw people off the trail. Which fooled a grand total of noone at all. In the immortal words of G. Dubya: "Fool me once, shame one me, fool me twice, can't be a shame-fooled-again."
Windows 8 is the reason Microsoft skipped Windows 9. We already covered this.
Windows Vista... Don't trust it. Not a bit.
Windows 7 is a solid and a really good OS. Never had any issues with it.
Windows XP has a lot going for it. For starters, the start-up sound is bang on. When I start a machine up, I want that sound. I'd have it in my car when I turn it on if I could get it working. Shut down sound is great a well. That background with the rolling hills looks great when Gens is windowed. Really helps you relax after a long period. 5/5. But there's no more security patches so even after you clear your browser history after a sketchy browsing session you could have spyware / viruses.
I'd go with Windows 7 or Linux / Mac.