Slot A and Socket 939 Motherboards.
I have used a number of ABIT motherboards over the years to build PCs. I have found them reliable, easy to set up and with reasonable documentation. I'm currently using AV8, KD7-E & KX7-333. The AV8 works fine with Linux, with drivers avaliable for the on board ethernet (via_velocity) and SATA (sata_via) controllers.