This one is strange. I chased around this problem for a long time and fixed it but I'm not sure why the fix works.
When I installed my Motherboard (Extreme II Zenith Alpha), everything worked BUT the POST took like 2-4 MINUTES to complete everytime I restarted Windows!
The solution was surprising. I had disabled the gigabit Ethernet port as I was only using the 10GBE port. Once I re-enabled the gigabit port (even though it wasn't being used and nothing is connected to it), the POST time decreased to only a few seconds!
I hope this helps some who can't get it to work and maybe someone out there as an explanation why I have to enable a port I have no intention of using.
