BTCMarkets is one of the larger and more reputable Australian Bitcoin exchanges.
They have recently shifted their focus to add more popular trading pairs that give breadth and depth to their trading offerings. Fees are the big advantage with this exchange with a reasonable to non existent set of charges for withdrawal and deposit and average trading fees at 0.22%.
Every single transaction is traceable and irretrievably stored in the blockchain.
Your coins and deposits are available and tradable 24 hours a day, 7 days a week.
The registration is free, depending on the provider there are different fees for the trade.