Its worth noting that this problem also didnt occur until I installed the 10.6.2 combo update. I have had this list stored away for some time, but default BIOS settings worked before updating so I didnt even think to look into that as a cause at first. Here is the list I collected from a few places of suggested settings:

IOAPTC – enabled
Execute Disable Bit – enabled
Max CPUID Value – disabled
On-chip IDE Controller – enabled
PCI Bus Master – disabled
On-chip SATA Controller – IDE
ACPI Function – enabled
Standby – S3
HDD S.M.A.R.T. Capability – enabled
CPU Enhanced Halt – disabled
CPU Thermal Monitor – disabled
CPU EIST Function – disabled
USB Keyboard Function – enabled
USB Mouse Function – enabled
SATA RAID/AHCI Mode – AHCI
Onboard SATA/IDE Device – AHCI
HPET Mode – 64-bit Mode