I'm currently using an HTC wildfire S, and am very happy with it.
As I type this, it is connecting my laptop to the interweb in a very dull meeting about finance (we've done the bit about aeroplanes, but I have to sit through the finance).
Tiny, good screen, excellent sensors, workable GPS and compass, more than enough computing power. The android aviation tools App is a particular favourite with me, as is Google Skymap - both free, as is the task killer I find essential to stop the battery being drained by lots of apps that didn't close properly (this seems to be a standard Android issue, not just this phone).
Grouches are small: I'd prefer a slightly bigger screen (probably the desire I'd guess, but that is more expensive), it does need charging daily and is best plugged into the laptop to continuously charge it whilst using it as a WiFi hotspot, volume could be a little louder.
If somebody nicks it, I'll probably trade up to one with a slightly bigger screen, everything else is superb and much as I loved my previous Nokia E63, that has been relegated to the local simcard when I'm abroad.
For what it's worth I have it on the 3 oneplan; £25/month giving me unlimited data, 2000 minutes and 5000* texts per month. Phone was thrown in on an 18 month contract. However, as the OP is in Australia, 3s rates in the UK are probably pretty irrelevant to the discussion.
G
* Is it physically possible to send 5000 texts in a month?