This is very interesting because I was looking at something recently about a line of Apple Servers that currently have a dual-core model but the quad-core model was hinted at down the line. Will be interesting to see how it all pans out. Presently I think AMD kicks Intel's backside in the dual-core war. So with the quad-core models on the horizon it will be interesting to see if Intel can step back up.
Honestly, though, quad core is so far away from me at this point it is even hard to think about. I have long since retired from living on the bleeding edge of computing.
I will wait and see who comes out on top and then in a few years migrate that way.