I agree fully with skuzzy. I have had WinXP 64 bit for over a year and it is a royal pain. Although Aces High will run fine on it, you will have trouble with peripherals, some install programs, and it does mysterious things at boot up causing random beeps (meaningless but REALLY annoying) over the past year and so on. I installed a second hard drive with 32 bit Windows XP over 6 months ago and it has been much better.
Translation of above: they can keep Vista for two more years or until they get it right. Period.