Okay you are some what putting subjective analysis onto them.
Joe Biden: Agreed he was a loser in Presidential politics, but Obama picked him for his experience
Sarah Palin: Highly Popular Alaska Governor, don't really consider that position a losing one.
Al Gore: You are right here in that he was a loser in that he had a failed Presidential bid.
Dan Quayle: Was a very popular and highly electable Indianan Senator.
But I will remind you that Obama was probably pretty close to picking Hillary Clinton, and might dump Biden this year for her. Obama however choose Biden instead of Hillary for his foreign policy experience and to boost his credentials, however after the economic crisis that became null.