In 2008 I think the Democratic Presidential nominee will get between 45%-48% of the vote in Arizona and should top 40% in Montana. There a number of states which will remain out of reach of the Democrats, however, a good Democratic campaign could hope to get over 40% of the vote in the following states (in order of likelihood) -
1. Indiana
2. Kentucky
3. Montana
4. Kansas
5. South Dakota
6. Texas
7. Alabama?
The dems should break 40% quite easily in Texas this time. Bush isn't running, so there's no home-state advantage, plus the GOP has done a good job alienating Hispanic voters the past few years. Keep in mind the dems won't even come close to winning it, but they'll probably hold the republicans to around 55-57%.