I think Romney was certainly the most electable in 2008. Not only did he have an economic background in a very economic election, it would have also been harder to call him Bush's third term. He never voted for Iraq and its not like he had a history of having to support Bush initiatives like McCain did. I think Romneycare could have been a big political ace for him too. Romney's plan was always pretty similar to Hillary's proposed plan and I'd think he could draw in a few more of the disaffected Hillary voters than McCain did, probably enough to prevent a desperate move like the Palin selection. I'm sure his financial background would have hurt him a bit, but at least he could actually propose a credible plan; remember how McCain's best idea was to suspend his campaign? And it would have been MUCH harder to attack him on his background; when financial industries are close to toppling right and left threatening world depression anyone with a brain would think twice before beginning the "greedy financial profiteers" nonsense on a public platform.
I can't agree here. McCain was the strongest candidate against the Democrats in every single poll I saw in 2008. McCain was the only candidate who ever ran ahead of a Democrat in a poll in 2008. McCain's problem was picking Palin and not recognizing that the hard right conservatives weren't going to bolt and be responsible for the election of one as liberal as Obama.