In planning DevDays (and FogBugz World Tours, for that matter), I've always wanted to go to Australia, but since the cost of travelling there is so high, it's very hard to make it work (financially) for the number of attendees that we might get.

What are some of the biggest developer conferences down under? How many people go? Are there any conference organizers in Australia or even New Zealand who are great at drawing a huge crowd? How much do conferences typically cost (to attend)? Is Melbourne or Sydney a better bet?