The AP's Ron Fournier isn't impressed with the Biden pick:

After all, Biden is anything but a change agent, having been in office longer than half of all Americans have been alive. Longer than McCain.

And he talks too much.

On the same day he announced his second bid for the presidency, Biden found himself explaining why he had described Obama as "clean."

And there's the 2007 ABC interview in which Biden said he would stand by an earlier statement that Obama was not ready to serve as president.

It seems Obama is worried that some voters are starting to agree.

Then there's this telling paragraph:

A senior Obama adviser, speaking on condition of anonymity, said his boss has expressed impatience with what he calls a "reverence" inside his campaign for his message of change and new politics. In other words, Obama is willing - even eager - to risk what got him this far if it gets him to the White House.

Or it means Obama understands that unless he shifts into serious campaign mode, John McCain will swamp him. Fournier's view is certainly one way to look at the Biden pick. And if Obama loses, that's how many will look at it.