Well... I worked for a Sydney-based ISP for 4yrs (so in general know the ins and outs) and instead chose to signup with Internode (after doing about 2mths of research) and have been with them for about 2-3yrs now.
Internode is about 3 light years ahead of the rest when it comes to network performance, reliability, support, expertise. They were also the first to implement ADSL2 and ADSL2+ and are 1 of very few (handful) ISP's (especially privately owned) that have their own international network links. They have plans for VOIP, Video-on-Demand, 1 of the biggest gaming servers, free unmetered downloads and radio stations etc etc. Simply put, they care about you like no other company can/does.
Checkout the /Internode forum area on http://forums.whirlpool.net.au I simply wouldn't be with anyone else.