I agree on overkill, but it'll be nice to be able to say, I suppose.

I currently 3-box with a 2.8GHz Core2Duo and 3GB of RAM w/ a nVidia 8600GTS 512MB card (I have 2 for SLi, but it doesn't help performance in WoW, so I rarely use SLi) running Vista 32-bit Ultimate. No issues at all w/ lag or anything. Just a perspective.