I'm thinking along the same lines as you, wireless is good enough and for us (we don't download much) it works out cheaper than most fixed line plans I've seen. Although it is a bit slow for streaming video or if you want to connect more than one computer at a time. To me, it seems like the longer we go without the fibre the less likely I am to sign up for it...
For others though, has anyone contacted Telstra about getting a phone service under the universal service obligations? I've read that they have to provide you with a service at the same prices as a normal phone line. Since we don't have phone lines here, they should provide you with a fixed wireless service which is basically a mobile phone with a normal phone handset plugged into it, but you would be charged the same as if it was a fixed line rather than the mobile rates. I haven't looked into it since our mobile bills aren't too bad, but if you're paying a lot more than normal it might be something to look into.