I have given up to install pfSense 2.0 on a system with the Intel board DH61WW. It looks as if the problem is the newer 82579V NIC, but it might also be s.th. else.
Nevertheless, Fedora 16 installs almost without problems. The system freezes if the onboard NIC is active when starting the Fedora Live CD. After disabling it, installing the OS, and updating the system, the NIC can be activated again and then the system and the NIC work smoothly. There were too many patches to see which drivers and chipset related packages were updated.
There is a short article on phoronix.com about FreeBSD on Sandy Burst systems, which seems to suggest not use Sandy Burst boards at the moment, although none of the problems described there seem to be relevant for my setup.