Most Republican County in Each State in 2008

[Verily]

I don't know all these counties by any means, but it seems that Sussex NJ is the only one where wealth is the key factor. Although one might say this about Washington WI, in a kind of different way.

Indeed. The list is a remarkable sign of the decoupling of upper-middle class status and Republicanism, or alternatively lower-middle class status and Democratic-ness, since the 1970s, as well as a remarkable sign of the modern and increasingly strong urban-rural divide.