Surely there is no real question. Anywhere that has "real" powder and does not have to rely on snow making has to beat every resort in Australia. I will be able to tell you soon.
Also, I am pretty sure that Funnel web isn't the longest ski run - we wish! And most of the time you cannot ski it and when you can ski it you trash your skis.
The "longest ski run in Australia" finishes at Friday Flat and you cannot ski from Funnel Web to Friday Flat.