The next service pack of Windows XP is due out soon. The big question is whether you should upgrade. If you don’t update Windows XP then what’s the worst that could happen? You could find that a hole in XP might get exploited by a hacker. Sure this is a risk, but that may not be so bad, since you could be running a secure IT infrastructure.
If you would like to update it gets very complex. Even though XP SP3 is simply an update to XP SP2, it will need to be tested and rolled out eventually to every desktop. Now if you are going to run compatibility testing and rollout a service pack then you may as well upgrade to Windows Vista SP1.
The only reason now to stay with Windows XP and install the SP3 service pack is that your hardware and applications are not Vista-compliant.