@meso @sally >kgpe-d16 was the dual cpu one right
It supports 61xx, 62xx and 63xx Opteron CPUs.

61xx and 63xx sucks, but you can't really find those CPUs anyway.

>I somehow arrived at KGPE-D16 being the best motherboard in existence
This was because it is - it has 6 SATA ports and 8 SATA/SAS ports (that do not work without an added SAS card - I hope for free software for such card of course), firewire, fits 2 RS-232, has enough 4-pin fan headers, supports up to 256GB ECC DDR3, fits 2x 16 core CPUs, dual gigabit etherenet and is also reasonably priced, as you can't get G34 coolers anymore, but modding on a cooler to fit isn't hard.

The drawbacks are that there are limited PCIe ID's despite enough sockets, although I haven't run into that, no integrated audio and not enough USB ports (although there are enough usb headers).

I looked at 4 socket supermicro boards, but the lack of PCIe sockets and SATA ports really kills such boards.