get telstra cable unlimited*
they lowered their pricing for yet another $10
so its now $59.95
its got free content in regards to GameArena. They have like up to 100 servers dedicated to games and don't count towards your limit. You can also download demos' for free and other stuff without conjuring up to your monthly download limit.
You can also download of files.bigpond.com with the likes of Linux ISO's for free...
Aside from those two prominent sites, they also have entertainment sites and a variety more.
Optus may be great, but in terms of content, they are heaps poor on it.
Not to mention the 28kbps cap they impose after you hit the limit. On telstra you get shaped to 64kbps which is usable as opposed to Optus' 28.
Also, alot of people might say telstra has bad customer service, but why would you ever need to phone them aside from the slight occasional "what happened here" stuff.
I have also read, Optus disconnects people/ban them from their network when they have been found out to be sharing illegal files on the P2P network such as Kazaa.
So i wouldn't risk optus.
If you can get cable, get telstra, its bloody worth it. However if you're looking at ADSL if you don't have cable, I suggest joining Netspace or iiNet. They use PIPE and don't have bad plans as well!