Welcome palms. If you new computer can do a credible job of runnng Vista, then I definitely would upgrade. You can check out its capability in this context here
http://www.microsoft.com/windows/pro...a&mg_id=20029b and here
http://www.microsoft.com/windows/pro...uirements.mspx. Be aware that your HP may have some sort of restore partition--which is unlikely to be functional after upgrading to Vista. Also, be aware that if you ugrade XP, then you are not supposed to use the program again no matter how you install the upgrade (i.e., some ways technically will not invalidate your XP product key).