Getting the best exchange rate when transferring funds can make a huge difference when moving here - remember this is your life savings we're talking about. You'd be surprised how much difference it can make, simply by shopping around.
As with everything else, doing your homework first is the key. Research the historic rates and be aware of upcoming factors that can affect the exchange rates.
Some currency exchange companies will allow you to fix the future rate that you want the conversion done at - and if the exchange rate hits that level, the transfer is done automatically. It is even possible to have an Aussie dollar account set up in your home country. Speak to a currency expert at any of the major companies - their advice is free of charge and you're under no obligation to use them.