I plugged the text of the speech transcript into wordle and got this result:

The main theme of the speech is clear from the cloud: the promise of America. It’s worth noting that Obama uses that word to refer to an ideal, a description of the American Dream, which put simply is that anyone can succeed here if they work hard. It’s not a mere litany of government handouts, as others have insinuated, but rather an appeal to the idea of America, its immigrant roots, and it’s fundamental character.

And it’s also worth noting that Obama drew a sharp distinction between himself and John McCain, firmly establishing the fundamental case for why Obama-Biden is indeed an agent of change, whereas John McCain would be in all respects a Bush Administration third term. As Obama forcefully said, “change doesn’t come from Washington; change comes to Washington”.