Here at the winery we use SCO Unix as one of our servers. Works on our XP machines by virture of a piece of softare called DejaVU NT. It emulates the screen and connects the Windows machines (as clients) to the SCO Unix server. Not much for any graphics, but does work for what we need it for.
XP is just fine. I run newer version browsers on it as well, such as Firefox and a new one called Maxthon. Really kind of like the Maxon of them all. You can even run Chrome on XP if you like. Remember, there are MILLIONS in other countries that are running and will continue to run XP. Companies, like the one I work for, simply continue to run XP as it is stable and works for what we need. Sent to you from my XP Home computer at work. Not issues, no problemo.