the power supply is serous overkill. if running everything at stock, this uses less than 300W
if you arent going to overclock, the SilverStone Essential ET450-B Bronze 450W Power Supply is plenty, and only AU$49
If you are going to overclock, then the Silverstone 650W at AU$75 is more than adequate. -- 550 would be plenty,. but the 650 is cheaper.
I would consider a 2TB HDD. games now can exceed 100GB each.
Do you really need the DVD Burner nowadays?
If Wireless N is all you have, that one is fine,but I'd suggest ethernet for a desktop that isn't moving anywhere. If you have it, Wireless ac is faster than N