Hi Acord,
I agree with everything Scoop suggests regarding joining the Qantas FF program.
In your post you mentioned the possibility of maintaining your allegiance to Star by flying ANA between SYD and NRT. ANA have recently withdrawn all services from Japan to Australia. Which should make it a lot easier to decide.
By joining oneworld you will also have the choice of flying SYD-YYZ and SYD-NRT with either CX or QF, depending on how much time you like spending on planes and in lounges.
But who ever you choose to go with, welcome to Australia. Hope you enjoy your time here.