It depends very much where you are in Melbourne, TPG are good in some areas, Talk BB, seem to be gaining a foothold in some. You should start by looking at their web sites, and what speed they would indicate you would be likely to get.
I would also consider if ADSL is the right answer, I am in the Melbourne area, and I have great performance out of Telstra Cable Extreme, with speed about 120meg, and it is not badly priced if you can get it.
The other thing to consider if you are not a high volume user, and likely to travel a fair bit is converting to 4G, then you would be able to take it with you when you travel.
Why do you want to get naked 
