[campbellcj]

Of all the Windows flavors, XP (and 2003 Server) has been the most stable in my experience, and the UI and feature enhancements -- although relatively minor -- are a pleasant upgrade. I have had virtually no software or hardware compatibility issues in recent years, although we keep most everything pretty current as an element of being in the software/IT biz.

That said, I rarely see value in doing OS upgrades on older hardware, especially when you factor in your time and money to reconfigure the system and potentially reinstall or upgrade your apps.

I also strongly prefer to do a clean reformat/reinstall when switching OS versions, which typically occurs after a few years' time span. In-place upgrade installations leave a whole lot of baggage on the system (Registry clutter etc) and can also lead to strange issues with permissions, orphaned services, etc.

Unless you plan to either upgrade or replace the hardware concurrently, I would think twice about upgrading an existing machine that is doing its job!