The Eagle's Wings

Let's begin with the Die-Hard States - those states in which one candidate holds a nearly unassailable position against the other. For the sake of convenience, we will use the Tradesports odds to determine membership in this category. If Bush is given a 90% or greater chance of winning a state, we consider it "Die-Hard Bush." If it gives him a 10% or lesser chance of winning, then we will consider it "Die-Hard Kerry".

Here's a map of the hardcore:

Bush has 19 states in his pocket while Kerry has 7.

Bush's 19 states have an estimated combined population of almost 81 million persons. That's about 27% of the American population. They control a combined total of 157 electoral votes which represents about 29% of the electoral college. Within these states, Bush enjoys an average polling margin over Kerry of +23.04%. Here are there stats, in descending order of their preference for Bush:
Utah: +39% (65.5% - 26%)
Wyoming: +36% (65% - 29%)
Mississippi: +31% (61.1% - 30%)
Nebraska: +31% (61% - 30%)
Idaho: - +30% (57% - 27.5%)
North Dakota: +30% (62% - 33%)
Oklahoma: +29% (58.5% - 33%)
Alaska: +26% (56.5% - 31.5%)
Montana: +25% (56.5% - 32.5%)
Kansas: +24% (58.6% - 35.3%)
Indiana: +21% (58% - 36.6%)
Texas: +20% (56.75% - 36.5%)
Georgia: +19% (57% - 38.25%)
Louisiana: +17% (53% - 36%)
Kentucky: +17% (56% - 39%)
South Dakota: +16% (56% - 40%)
Alabama: +16% (54.5% - 38.75)
South Carolina: +10% (52.5% - 42.75%)
North Carolina: +9% (52.75% - 43.75%)

Interestingly, the state of Arizona is not in the "die-hard" category, despite the fact that Bush's average lead in the state is +15% (53.6% - 39%).

Kerry's 7 states have an estimated combined population of 57 million, which is almost 20% of the population. They control a combined total of 115 electoral votes, which is about 21% of the total. Kerry outpolls Bush in six of these states by an average margin of +16.56% (there are no polls available for DC).

Here are Kerry's strongholds in the same order as for Bush:
Massachusetts: +31% (29.3%-60%)
Rhode Island: +26% (27.5%-53.5%)
New York: +13% (39%-51.6%)
Vermont: +13% (38%-50.5%)
California: +10% (41.75%-53.25%)
Connecticut: +8% (39%-46.5%)

DC has not been polled, but it can be safely assumed that Kerry's margin would be closer to that of Massachusetts than of Connecticut. Also, Kerry is actually leading by a wider margin than Connecticut in three states where his odds are considered lower. Hawaii, Illinois, and Maryland all give Kerry strong leads (+9%, +9%, +12% respectively) and the state of Washington gives Kerry a +8% margin which is equal to Connecticut. However, like Arizona, these states are considered to be more "in-play" (though not very) despite the strong poll numbers.

I'm guessing that the distinguishing factor in such states is a greater volatility among the electorate, which makes a strong lead less reliable in the eyes of the market than in a state like California, which is pretty steady even if the margins are slimmer.