As I've said elsewhere, this election is shaping up to reflect elements of the 1976 and 1980 elections in different ways. Krauthammer posits that Obama is taking the path of Reagan v. Carter - with Reagan as the cool, calm, laid-back alternative to an incumbent scrambling to explain how the country had gotten into such a mess on his watch. The Obama campaign seems to have been successful in their tactic to link McCain to the Bush administration - thus pressing McCain into the Carter/incumbent role.
I think there is also a case to be made that Obama is, in a sense, too, playing the role of Carter in the 1976 election. Krauthammer hints at this as well:
[Obama] continues his clever convention-speech pivot from primary to general election. In a crowded primary field in which he was the newcomer and the stranger, he rose above the crowd on pure special effects: dazzling rhetoric, natural charisma and a magic carpet ride of transcendence and hope. [admittedly Carter could not be characterized as "dazzling", but substitute "folksy", "approachable", "homespun", "familiar", etc. - you get the point - Carter ran as a "one of us" candidate v. the incumbent/insider]
It worked for two reasons: Democrats believe that nonsense, and he was new. But now he needs more than Democrats. And novelty fades.
Obama understood that the magic was wearing off and the audacity of hope wearing thin. Hence the self-denial perfectly personified in his acceptance speech in Denver. He could have had 80,000 people in rapture. Instead, he made himself prosaic, even pedestrian, going right to the general election audience to project himself as one of them.
Ordinariness was the theme. His self-told life story? Common man, hence that brazen introductory biopic that shamelessly skipped from Hawaii grade-schooler to Chicago community organizer with not a word about Columbia and Harvard. His riff on American concerns? All middle-class anxieties. His list of programs? All pitched as his middle-class remedies.
Having said that, Obama is clearly no Reagan - in terms of sustainable charisma, leadership, political savvy or effectiveness. In four years, it will likely be Obama's turn to face his Reagan.