I don't have a favorite, either.
But if I had to choose, I guess I'd go with Australian. And that's because it's the easiest for me to imitate.
Not to over-estimate my abilities, but I'm not too bad at imitating accents. My best ones are English, Scottish, Irish, and Australian. South African is really difficult. I have to listen to someone before I can get into the right cadence and pronunciation.
The problem is once you speak in an accent around other people (well, Americans) they start asking you to perform on command.
Zaps all the fun out of it lol.
