The trouble with Windows is that it's been built from a no-security basis on up. Which means when they do put in security features, it breaks things. (And when someone keeps having to click "Yes, run it!" for Admin access even for changing the computer's time[1], they get used to "just clicking it", and you know where that leads.)
I'm not saying there aren't good things in there, but still using a Win98 machine and a W2K machine at home and predominantly on XP myself in both personal and work settings, I'll admit that I get annoyed by Vista when I have cause to use it and I get on with Seven mostly because it's less annoying than Vista, but wouldn't recommend it as a technical interface over XP. As someone who doesn't demand the latest games, XP is also sufficient for most of what I do (it's not actually getting worse, over time, just not getting better, so what some things now demand isn't easily provided, or at all, through XP...)
Anyway, that's me. And when I get a brand-new machine I'm going for a Seven (to return to the subject at hand). Unless I leave it long enough to see benefits to Eight to change my mind, but I don't foresee wanting touchscreen capabilities on any non-mobile device, right now. I'm not a smartphone user (I've got a Samsung GT-1080i... look it up... and only got that when I did because my even more archaic Nokia blah-de-blah-ten's battery was failing and it was cheaper to get a new phone) so a smartphone-like interface isn't something I'm keen to go for. I just know I'll be getting a lot of experience with it before I commit myself to a personal purchase, however, which is often how I've kept myself up with the technology curve (if not personally blazing a trail for everyone else to follow) over the last couple of decades. (Although my first Windows 95 machine was a bit of a leap into the unknown. I nearly stuck with Win3.11!!!)
So, anyway, I'd say Seven is your best bet, in a continuation of me just randomly repeating some of the advice already given. But horses for courses.
[1] I can see reasons why they shouldn't be able to do this, but the proper Windows way is to use Policies/whateverthey'recallednow for the Admin to restrict the feature, not to make it a hoop-jumping exercise for the average user on their own machine. And if (I haven't checked) the TIME and DATE commands in DOS still work without UAC intervening then pestering the person who has just clicked on "Change date/time" to get MS's own settings window to say "Yes, I want to do this" isn't helping any.