I agree, his actual policies seem a bit vague and I don't know if I agree with them. What I think is more important though is the effect it will have for America abroad in regards to their foreign policy and people's perception of the country.
Also it's a massive step for American society, just think if he was alive 4 generations ago, he would have had 0 rights, he wouldn't be allowed to vote and now Americans have chosen him to rule the country in their name.
Politics isn't really about Gordon Brown making speeches or people arguing in the House of Commons. It's about how the world is and how it should be. I study politics at university and it can be a pastime itself. Understood properly it makes the world a more interesting place. Obama becoming president is a massive statement of how Americans would like to see their country (and therefore the world) change.