I'd be more concerned about the lacking efforts by ZoneAlarm and Symantec for firewalls and antivirus.
At least we have other choices.
According to eWeek.com "Dangers lurk along Windows' 64-bit upgrade.........
According to this eWeek report, PC customers could void their warranties by upgrading to Microsoft's new 64-bit Windows XP.
Does anyone on CNET has more information about this???