Here's who I think the presumptive nominees should choose:

Obama: Governor Kaine of Virginia
McCain: Mitt Romney

Both of my choices have the ability to deliver a state. In Romney's case, it is Michigan. I should add that the last vice-presidential nominee who was chosen with the idea of delivering a state was Lloyd Bentsen, Michael Dukakis's running mate in 1988 against Bush-Quayle. That didn't work out, except for the vice-presidential debate ("I knew John Kennedy. John Kennedy was a friend of mine. And you're no John Kennedy.")

McCain doesn't like Romney, but that shouldn't stand in the way. Overseas fact-finding missions and state funerals are made for vice-presidents.