It seems Obama has selected Joe Biden as his running mate for the November elections. I think this was a pretty wise choice. You want your VP to aid you in areas that you're loosing the votes of moderates. Obama is losing votes b/c of a lack of experience, substance & aggression.
Biden was the most experienced of the democratic candidates, which answers Obama's extreme inexperience. On the other hand, Biden's quote ABOUT Obama's inexperience could come back to haunt the campaign. ""I think he can be ready, but right now I don't believe he is. The presidency is not something that lends itself to on-the-job training."
Obama is viewed, by many, as a speaker with style but little to no substance. Biden is viewed as very articulate and intellectual. Biden is considered an expert on the issues.
Obama promises to fight a clean fight. He hardly ever speaks boldly, instead using generalities and non-specific nuance to answer questions. After the Saddleback forum, Obama went down in the polls b/c people liked McCain's absolute answers. Biden is much more likely to tell you what he thinks. But he's experienced enough to not say anything way too stupid which would ultimately hurt Obama.
Ways it could hurt Obama...
1) If Hillary supporters get bitter
2) If Biden appears to arrogant
3) If it confirms Obama's inexperience
As an interesting aside, Biden was a potential VP pick in 2004, but instead suggested that John Kerry pick... You did NOT guess it... John McCain!