I'm on iiNet's 256/64 ADSL plan...3gb of downloads between 8am and midnight and then another 2gb between midnight and 8am. Trying to convince my parents to upgrade to 512/128 with 10gb peak/6gb offpeak...*drool*
Changing ADSL ISPs is much simpler now that there's something called Fast Churn -- if the ISP supports it, you can change ISPs for a much cheaper cost and with only about 4 hours downtime between ISPs.
As some have said, if you're considering getting broadband you really should check out
www.whirlpool.net.au , especially Broadband Choice and the Forums. Check out the forums, see what people are saying, find out which ISPs are connected to which peering networks (i.e. you'll probably want an ISP connected to PIPE (
www.pipenetworks.com) in NSW -- free downloads!
I personally use a Billion BIPAC 711-CE modem, bought it from PC Range in SA. Has USB and Ethernet, I'm using the USB and have had no problems.