I think with these you almost have to pick a state with a long-standing loyalty to that party. There's no way in hell WV is the last GOP holdout even if it was solidly behind McCain and Romney (or should we say against Obama), and there's no way VT is one of the last Democratic ones. I think a state like UT is probably the best choice for the GOP (voted solidly for Reagan and Romney almost 30 years apart ... It's a very Republican state), and MD or MA are good for the Dems.
That's a great point. MD/MA seem like excellent candidates at this point in time, though without the partisan history, I'd also think NY/CA fit in too
(for dems)However, historically the only region with electoral votes that couldn't be flipped in a landslide is DC
(so not a state). Other than that, MD/MA both fell to GOP landslides at one point or another.