Life Changing Decision

I have been offered a graduate student position at the University of Melbourne. I had applied for the position about two years ago and had already despaired of hearing anything in the affirmative, had gone ahead and gotten married, bought a house etc, when all of a sudden BAM! It is a good offer, in what appears to be a quality lab, with a well established and successful professor, an interesting research topic, and with a completion date in about 3 years. The stipend is extremely modest and what's worse, it is in a city of 3.8 million people. And, oh yeah, it's on the other side of the planet! We would literally have to give up, sell and give away everything, and take along only what we can carry. Our home, our cat, our cushy little jobs... And yet, we are seriously considering accepting the offer. Adventure, excitement, and really wild things!