Great ARticle on the Biden selection.
I always thought that selecting a Vice President was all about offsetting one's own weakness. Biden brings two things to the ticket, foriegn policy knowledge and time in service. Biden is not an executive and never has been, and not I said foreign policy knowledge, not experience as he has none.
Conversely, Biden brings loads of baggage that will be roundly exploited by McCain.
Now that I think about, Biden could bring the advantage of being a better target that Obama, making Obama look less like a jerk than Biden.