Good deal from Optus if you can't get wired internet and are in a internet blackspot like myself.
Works out at $70 for 50GB PLUS you can buy up to 5 x $10/10GB top up packs, making it $120 overall per month on the 24 month plan. Previously this plan used to be shaped after 60GB but now it is only shaped after 100GB.
Be warned though, if you ever run into any billing issues, their customer service department is something else.
Vivid wireless $89 unlimited.
http://www.vividwireless.com.au/