Well, EFFalcon and myself both use Netspace, as well as many other happy customers I know of. You're looking at a hefty setup fee (with any ADSL ISP, not just Netspace), perhaps upto $400 including first months fees. The Netspace 512/128 plan is pretty good, but thats from someone who has lived with 56K for many years
Netspace, IInet, Westnet, Alphalink and a few other ISPs are all connected to PIPE and AUSIX, which allow free P2P traffic between these ISPs, and there is a P2P network setup. It will be nothing like unlim. cable, but it is better than 56K for P2P stuff.
As for quality of service, Netspace has been non-stop, high quality service for me, and you will get ~57KB/s from most sites (512k ADSL maxs out at about 57KB/s.. again, sucks if you've just come from 6000/128 cable)
Another thing too try is http://bc.whirlpool.net.au/
(formerly broadbandchoice.com.au). They have a decent search feature, so you can judge what ISPs offer what you're looking for and for how much.
Good luck with the move and getting some decent "broadband" ADSL :)