"Best" is a relative term. There are 2 chipsets, nVidia and Broadcom. I would choose a Broadcom chipset if you are looking for the most "corporate" chipset and I would choose nVidia if you are looking for the highest performance.
nVidia tends to go for performance and you will see more driver revs with their product. Broadcom tends to be more stable with fewer driver revs, but then it may not have all of the fancy features because its targeted at a corporate customer that wants more conformity
Is there any particular reason you want to talk about 3 diff mobos, all with nVidia chipsets from what I can tell in this thread about different chipsets for the Opteron? Have you considered using the new thread button instead of asking an offtopic question in a semi-dead thread?