I don't see why people are mentioning Klobuchar. She's very bright, but she's a policy wonk. I can't imagine that she would run.
Because she met with both the Iowa and South Carolina delegations at the DNC (what is the point of that if you're not at least considering a run for national office?):
https://uselectionatlas.org/FORUM/index.php?topic=158046.0
and said to the Iowa delegation "I can see Iowa from my porch".
[Granted, in that last article she's quoted as saying that she “loves being in the Senate” and is not planning a presidential run. But that's classic non-denial denial. Not planning a presidential run right now in 2012 doesn't mean that you're not going to start planning one in the future.]
Weigel on Klobuchar at the convention:
http://www.slate.com/blogs/weigel/2012/09/07/the_great_race_for_2016.html
I guess there needs to be a female candidate if Hillary doesn't run. But, ultimately the question is, who is excited about Amy Klobuchar? She does good work in the Senate, but I've never seen a whole lot of vision or charisma that would translate to a Presidential campaign.