I had xp and it was good, but it's outdated now. Vista is just... eww. When I had Vista, my computer literally got a new virus every other day and it eventually crashed. With Windows 7, I've only had one virus and I've had it for over a year. Plus it has a lot of customization features. Don't know about Windows 8 though. It seems like it's only for touch screen computers. Mine's not touchscreen, so no need for it.
You have enemies? Good, that means you stood up for something.
The core of each OS consists of almost the same thing.
Vista was very unstable and didn't work that well when it first came out, but ever since SP1 came out (which was a while ago) it's fine to use and there's nothing wrong with it. The more important questions are what can your computer handle, what can you get your hands on, and what do you plan on doing with your computer.
I personally use 7 on my computers but I have a few computers\VMs in my house with XP, Vista, Server 2008, and Linux.