I've got a BFG nForce 680i that I run OS X on. In fact, its now running 10.5.7 server, and is the primary server on my home network. It handles all the home audio/video, and other network tasks. I used iPC for my machine; other than iPC, the only other distro that actually worked for me was the original TOH RC2 10.5 Leopard release; now, I use iPC to install 10.5.6, and then install server packages, and finally update to 10.5.7 and use the ANV kernel. Works great, runs 24/7 and I've yet to have it crash on me.

Anyways, just wanted to let you know that you can get OS X running on the 680i boards with very nice results. If you haven't already seen, there is a great thread over at Insanelymac headed by a user that goes by the name of "Verdant" and it deals exclusively with the nForce boards. While I don't condone the extensive use of Insanelymac anymore, these in particular are some very nice threads for the nForce boards, and Verdant is very knowledgeable on the subject. If you need specific help with anything, let me know and I can get you more detailed steps of what patches, etc I used.

-geiman