Gary,
the possibility of a young, charismatic, black guy as the next US president has to be pretty damn inspiring.

Nan,
the needed change bit probably refers to the U.S. turning its back on the Bush years.

Gary,
that looks right.Michael Tomasky in the Guardian says:

His (obama's]message turned out to have the greatest resonance. Significant pluralities of Democratic and independent caucus-goers - he won 41% of the latter category - want to believe that someone can lead the country out of the current toxic swamp of partisan bitterness.

I see similarities with kev07.
Obama presents greater story lines with him and his family.

Congratulations Mr President.

I am not sure the need for change is a driving narrative with voters. I suspect many Americans are concerned about their international image and see Obama as a influential and calming force in that area. It is possible this may be why he is now being attacked for having no foreign policy experience.

Then again voters could just want competence. After seven years of Bush, competence and good governance would be a welcome change.

Cam,
Obama's campaign stump message is one of hope over fear and unity over division is a break with the past. Obama's claim is that he's a post-partisan candidate who can end all the nastiness and empty Beltway wrangling. The politics of "unity" is a reaching out to independents and Republicans.

Wouldn't the account you highlight-- the US's international image and seeing Obama as an influential and calming force in that area---strengthen Hilary Clinton's hand? She has the experience courtesy of the 8 years in the White House to stand up to the "bomb first, ask questions later" crowd that has dominated the GOP in recent years.
Clinton's campaign stump message one of it being a basic choice between experienced leadership for change and inexperienced leadership that talks about change.

The main media commentary interpreting Iowa is very much about change--another example

Cam,
this article suggests that Hillary Clinton may do more than attack Obama's lack of experience. What else can she do but go negative/attack, when most young people simply don't care for Hillary and they see Obama as a break with the past. Insider status, establishment support, and machine-like precision lost to pure grassroots passion and a more idealistic vision of what America could be

Obama's record features opposition to the war in his Senate campaign in 2004. Clinton and Edwards both voted for the war. Edwards apologized for that vote. Clinton never did. Iraq is a top concern to voters.