Interesting to note the voting in the poll - unless I'm mistaken there's only three Aussie respondents who voted for Kallis, and of them, only two support Australia. And from memory one of them is probably one of the biggest (if not the biggest) fans of Kallis on the forum.
I would be really tempted to go for Kallis, as I just have a thing for really solid guys in the middle order who put a massive premium on their wicket, they can be extremely valuable when the chips are down. And as has been said before, there's still a question mark over Hussey in different conditions round the world, and many people have pointed out in this thread the disparity in longevity (and experience). For some unknown, arbitrary reason I find Hussey really boring anyway, so Kallis' stoicism by comparison isn't a massive negative.
Of course, as successful as Australia is at the moment, there's obviously a fair argument that we don't need a player like that at present, so I guess it's just a personal preference on my part. Plus, he has a long-time corporate affiliation with Sanex, so our players would have beautifully soft and tender hands and feet.