Living in Australia like Adam Schiling, but at the opposite end of the country, Darwin, I agree with his comments about 3G. In fact I wouldn't buy one without a 3G chip. At the moment there is no 3G network in Darwin but we do have "Next G". We do have 3G phones up here but there are some features that will not work.
Australians will know what I'm talking about so I won't bore the rest of the world with an explanation about "Next G".
I don't know if I'll buy an iPhone or not. At the moment I'm not unhappy about having to wait, we will have 18 months or more for the thing to evolve and get whatever bugs there may be ironed out.
Third party application availability is a concern to me as well, I have seven on my Palm LifeDrive that I use quite a lot.
Before You Buy the iPhone...