For the moment, forget the speeches, forget how "influential" he has shown he is, forget the movement that he was able to create. Forget most of the things about this man that has made him popular and impressive from the observer sitting at a distance, moved and touched by his eloquence and charisma.
Focus instead on the most difficult question to answer: Who is Barack Obama and is he really equipped to be the man that can lead a country as important and as powerful as the United States? If the presidency is only just about the man and what he can do and how well he can do things, will Obama still be the one that can bring true change to a country in need of a true leader?
With that thought, and if you had but one article to read about this man that goes by the name Barack Obama, running a movement against the traditional politics of Washington, read this one by Marc Andreessen:
Then you'd be even more glad, and it would even make more sense that this man has the charisma, eloquence and the influence to make people believe. Again.