Admittedly, I endorsed Joe Biden for President before the Iowa Caucuses. Certainly, it wasn't because he voted in favor of allowing Bush to invade Iraq, it was despite that fact. On a broad range of issues, I have found Joe Biden to be a thoughtful and articulate U.S. Senator. He and Chris Dodd seemed to me to be the most experienced and well-grounded candidates and I picked Biden.
Geographically, Joe Biden doesn't add that much to the ticket, as I would expect for Obama to win, that Delaware should be considered a given. Perhaps Biden has some traction in western Pennsylvania and northern Virginia, but even that is mere speculation. What Biden does provide, is an intelligent and competent individual who could take over the Presidency if Obama should suffer a fate like JFK. At Biden's age, it would be ludicrous to assume that after eight years of an Obama administration that he would be the favorite for the Democratic nomination. Biden is selected on the basis of his ability to be an excellent Vice President. What this signifies, is that Obama wants competent individuals in his administration, and he's starting out with his V.P.
Biden, a nice choice.