I decided to take the plunge and ordered Caller ID on our home telephone this week. It costs $6/month which is not that cheap considering you just get a bit of extra data with each call, but I think with the savings we are making with using VoIP for virtually all of our phone calls it will be a useful addition.
Telstra have a deal that for the same price, you can actually choose two services, so as well Caller ID (or Calling Number Display as Telstra call it), I ordered a T1000C rental phone. This phone can display the Caller ID information, and also has the advantage of not requiring external power (unlike our existing cordless phone), so in the event of a power failure or flat battery we will still be able to make and receive calls.
The only configuration change I needed to make to my Sipura 3000 was to change the ring-tone back to a more conventional Australian ring. Without that, the telephone was losing the Caller ID info after the first ring.