I'd say King William V will be the last King of Australia.

Who wants to bet?

If they don't skip charlie/only give him a few years, then I'm not sure William will get a shot.

It would be a mistake, but I can see a politician with delusions of grandeur railroading it through. The problem, as always, is how do you ensure that only those who wouldn't physically turn your stomach get through?

President Abbott?

If the Queen lives as long as HM the QM, then Charlie may pop his clogs before he gets a chance to rule.

I'm saying Elizabeth II will be the last monarch of Australia. I'd put money on it.

Nah - I reckon when Lizzie 'retires' (using the traditional method of dieing) it will kick off the Australian Republican movement - but the transition wont be instant, so Charlie or Wills will get a year or so in the gig before they are officially written out.

I'd put money on Australia being a republic within 5 years of the death of Elizabeth II though.

I think Australia becoming a republic is a long way off. Financially Australia is not as sound as it has been recently and the immediate future is a little questionable. It will cost a huge amount to become a republic and I don't think any of the parties would go for it.
to becoming a republic in the next 5 years.

I cant see it happening anytime soon, the Government hasnt got the money to do it as the costs would be huge. Its completely pointless and will achieve nothing, besides support for a republic has been dropping.

What are the benefits of being a republic over having the queen head of state. How much does she get a say in the running of the country etc?

Anyone care to elaborate on what these massive costs would be, other than holding a referendum and changing the word "governor general" to "president" on the stationery?

presidential elections perhaps?

Hold it at the same time as federal elections.

What about cost of maintaining a president and his / her office? What is cost / benefit?

Probably not in the next 5 years but it's inevitable with Australia's demographic quickly becoming less "Anglo".

Depends on the presidential model. At the top of the range is French/US model which is expensive, but there are cheaper models for those on a budget. As executive power is with the PM in Australia, I would recommend the budget model.

It would potentially cost the same as maintining the current office of the Governor-General.