I have an Optus Internet and phone cap. All calls (no matter which network) inclusive and a big download amount. It's an old one but they have similar ones still. Service is great and I pay same amount every month. Very easy to budget.
Probably no point me posting because everyone is saying avoid telstra, but I am with telstra and have never had any problems and have always had really good customer service. I like my plan, we have a bundle with home phone and calls, and 100gb adsl 2+ then slowed for $88 per month.