Via Polstate, a county by county comparison of the two-party Presidential vote in Texas for 2000 and 2004. I actually started some work on this very topic myself just before leaving town for Thanksgiving. You can see my spreadsheet here. I've added in data calculating the Republican Partisan Index (RPI - see explanation here) to get a feel for which counties are becoming more Democratic and which are becoming more Republican. In the spreadsheet, a negative RPI means that county voted more Democratic than the state overall, and a positive RPI means the county voted more Republican than the state overall. A negative "RPI Change" number means that county became more Democratic between 2000 and 2004, at least in terms of the Presidential vote. Note that this does not necessarily mean anything in absolute terms. For example, the infamous Glasscock County, which Lasso has noted as being one of the five most Republican counties in America, actually saw an increase in Democratic votes and a decrease in Republican votes between 2000 and 2004, making them the only county in Texas for which that was true. Of course, in absolute terms, the vote went from 528-39 in favor of George Bush to 488-44 in his favor. Not something on which to hang one's demographic Stetson, that's for sure.

Anyway. From my perspective, the counties of greatest interest are (in no particular order) Travis, Hays, Dallas, Fort Bend, Harris, Caldwell, Williamson, Bexar, Tarrant, and El Paso. I'll have some more organized thoughts on these places in the coming weeks, probably after the holidays.