Just because you get a new computer that has Windows 7 or 8 (ick) on it doesn't normally mean you can't run XP. It's only a matter of drivers. If you search in the usual places, you can find drivers for almost anything. I just bought a new Asus laptop with Core i7 Quad hyperthreading (very nice) and XP runs like a champ on it. All drivers working, no problems in Device Manager.
In fact, there are places on the 'Net to download Driver Packs for XP that make it work on almost all of the new computers.
I have no reason whatsoever to use Win 7 or 8. They are bloated and awful. Win 7 is bloated with all the DRM stuff, and Win8 boots a little quicker, but look at at that AWFUL Metro interface..... Yuck.
I routinely refurbish computers, and the ONLY thing I would even consider loading them with is XP.
Don't worry about the Fear-Mongers trying to scare you about end of support! A company called Arkoon has a product called Extend XP that provides security against hackers, worms, and viruses. I think AVG will be just as good, but for free.
Long live Windows XP!