We learn here that though there were "bad" Persians who threatened the Jews with extermination, no Jewish lives were lost, but over 75,000 Persians (mostly innocent, I'm sure) lost theirs.
We should also recall that it was a later "good" Persian king, Cyrus, who, in the last two verses of the Bible, proclaims "The Lord God of Heaven has given me all the kingdoms of the earth, and has charged me with building Him a House in Jerusalem, which is in Judah. Any one of you of all His people, the Lord his God be with him and let him go up."
Similarly, it seems incumbent on us to remember that in Hitler's Germany there were the "bad" Germans as well as good Germans. And the Germany of 2011 is not the Germany of 1933. We Jews have not held the Persians forever guilty of a perceived plot of annihilation. So must we Jews not hold Germany forever hostage to its history. At some point, in our hearts and minds, Germany will have to be "set free." As a King Cyrus followed a Haman, so can a benevolent Germany follow a tyrannical one.