My sister moved back to Montreal from New Zealand last Christmas, and they had all their stuff shipped over by boat. It took months to arrive, but it was the cheapest way they could find to bring everything over. They also sold and gave away a lot before coming back, as the cost of shipping a couch, for example, was more than simply selling it for cheap and then buying a new one. You may have to calculate everything space/weight wise and see what works out best for you.
Hope that helps!
yeah shipping would probably be the cheapest although you should check with fedex in Australia because they now have these crates which are of fixed size which cost I think around $200 to send by air... there are like 10kg and 25 kg boxes