Hi there,
I personally would talk about the asylum seekers issue or any other political matter (Rudd's populist electioneering tactics, carbon tax, lack of women in Abbott's front bench etc). However, if you want to steer away from politics, I would advise that you consider the war in Syria or perhaps some other major conflict in the world today? As a previous post mentioned, look at the AGE and see what topics you are interested in. Also, consider the context that you are studying (I assume you're in year 12 next year) and perhaps write something that you could use for those essays. You will be required to research your particular context and knowing a pertinent issue already, through your oral will be beneficial. One last thing, year 12 English can get very, very crazy so writing your oral during these holidays will give you an advantage. If you have any questions like how interesting ways to start or anything like that, please feel free to PM me.