I don;t know if this effects you but the 6850s have dropped price, are they dropping prices in Sydney? They currently are cheaper than the 460's in the States.
Also, you should look at picking up a 2500(K) if it is cheaper by a lot since they 2500 performs nearly as good as the 2600 but also it is the best bang for the buck.
I also recommend checking out the Samsung F3 1tb if it is cheaper. Is that the Seagate Barracuda 7200.12 or just the 7200? If it isn't the 7200.12 go with the F3 or get the 7200.12