I have about 99% accuracy in spotting Aussie and Kiwi accents. I sometimes just a little confused with South African or when Australian/Kiwi accents become more North Americanized.
The weirdest thing after coming back to Canada after just over a year away was getting used to hearing the Canadian accent again. I was so used to hearing Aussie speak that it started to sound normal.
Speaking of accents; when I was living in Australia I had a woman a grocery store call me an American, and when I corrected her she got upset and asked if there weren't allowed to call Canadian's American's? I guess people don't grasp the fact that while there's a lot of shared history, culture, and just a line that divides us there are differences.