Biden is a mistake. I'm not sure what Obama was thinking there. Biden has a brutal tendency to shove his foot in his mouth....things like "Delaware was an original slave state" when explaining why he appeals to southerners. Plus, he roasted Obama on inexperience and a poor plan for Iraq during the primaries, all while praising McCain. The VP pick is rarely significant, but I think Obama could have done better.
Now, I'm really hoping McCain goes with Hutchison. If he does this, the election would be effectively over.