I left Windows years ago, and so am not extremely familiar with Windows XP, although for a short time I had an XP machine along with my Mac (the XP machine is now in my closet). But I recently had the opportunity to see someone update an XP machine they received, to the most current available updates. The process took ridiculously long, MUCH longer than it would've on my Mac. Then, trying to install audio applications and their drivers was a nightmare. Windows would go through the entire install process, and then when it was finished it would pop open the Wizard, as if the install process for the driver needed to be done all over again. At this point, you're wondering "Should I install again, or will that just screw stuff up worse". Then, after you make that decision, Windows wants you to tell it where the driver is! And of course, there's no reason why a casual user would know where the hell it was put. And for the brief time I had an XP machine at home, side by side next to my Mac, there were other obvious ways that the Mac was superior. Plug in a usb flash stick on the XP machine, and it needs a driver. Then after installing the driver, plug in a second usb flash stick that is the exact same brand and model as the first one, and again XP wants a driver installed. The Mac never required any driver installation. Oh, and with my scanner....I would use it once with the XP machine, and it would work. The next time I'd go to use it, Windows would claim there was no driver installed for it. Fortunately, I finally found a driver for Mac OS 9 (since the scanner company never made an OS X driver, which is why I was previously using the scanner with the XP machine). Guess what? It works flawlessly in Classic mode every time! So, even OS 9 bests XP in some ways. And OS X is light years beyond OS 9.
Add to that little things, like being able to save a file as a pdf, right from the desktop, and being able to zoom in on the desktop, take a screen shot, or take a screen shot of a particular part of the desktop, all without any extra software, just using what's included with OS X.
The longer you use OS X, the more you'll see how much better it is than Windows.