How close were presidential elections?

Slashdot points to this great analysis at MIT by Mike Sheppard:

This page answers the question: 
What is the SMALLEST number of total votes that need to be switched from one candidate to another, and from which states, to affect the outcome of the election?

And that's what election strategies are all about.  45% of us, no way are we voting for a Republican candidate, because we really do believe in the values that drive the Democratic party (though we might vote for an independant).  45% of us, no way are we voting for a Democratic candidate, because we really do believe in the values that drive the Republican party (though we might vote for an independant).  So, who we gonna swing and where?