As someone who works in the telecommunications industry I completely agree with bozodos as well as a few of the other guys here
Within the last 8 years the need for faster speeds and greater download capacity as grown.
I've seen plans go from 400MB to 1TB on the HFC network and Unlimited on the ADSL network. Speed wise, companies like telstra and optus are now offering docsis 3 (up to 100mbit/s) but these speeds are not available to everyone. Telstra only offer this to Victoria (as far as I'm aware) and Optus to the QLD, NSW and VIC (but even this is limited to older suburbs)
Even though the current pricing/download quota that is being advertised is expensive (they will eventually go down, they always do) , I believe the NBN is the way to go in the long run
The pipes to overseas is not the only thing that needs to be upgraded. These can be upgraded to handle anything Australia has to throw at it, the telco's still need to upgrade their international capacity.
If this does not happen, the upgrade to the pipes are useless. Then it also depends on how the telco's route their traffic.
I have adsl2 and live 4-4.5kms from an exchange, line sync at best is 4meg, I say bring on the NBN
There's a lot more I could add but my brain's currently fried after a 12 hour shift