Believe it or not, but the best core/md motherboard I have found (out of 3 different ones) is the ASUS P4P800.
Its a single core 2.6 ghz system with 1gb ram, and a 1 TB drive. The video card is an old AGP Nvidia 7600GS card.
I have also tried other newer micro, 2 with HDMI or Component ports, but the video playback sucked and found other problems with the hd audio port (one was an XFX 630i, and the other was a new Gigabyte motherboard.
I have to admit that I am not a very good linux troubleshooter. But time will probably change that.