I've been with many different ISPs in my time, but I went with iiNet about 4 years ago, and have never looked back. They were the first to introduce VOIP, giving flat rate calls nationwide. Occasionally you get down time, their DNS has fallen over a few times.

iinet - used to have huge problem with them when I first signed up as they had nowhere near enough customer service people on their phones. However, they seem to have cleaned up their act somewhat, and the internet service they offer is really pretty good. I have my home phone with them too, which does drop out occasionally, but overall, I'd say I was pretty satisfied with the way iinet runs their service