These flies have always fascinated me. I have only seen them since I have lived in Queensland and out in the bush, however, reading up on them I discover that they are common in Sydney - I had never seen one in Sydney! Although the Robber Flies look pretty sinister I quite like them (well, perhaps more sinister if you are another bug, prey!), they do a good job eating bad bugs.
Here's a link to a picture and some information on the Robber Flies. (The image at left is from this site.)
I was chatting with mum one day and she asked me about the flies that she'd seen in the house. I asked if it was striped down its back? She said yes, and it had big, red eyes. I asked my entomologist friend about these flies and he told me they are Sarcophagidae (Flesh Flies). I notice the flies if there is the smell of dead mouse in the ceiling, and sometimes I only know there's a dead thing up there because a fly appears in the house. Usually only one fly per little dead body. They are called Sarcaphagidae (Flesh Flies). They are quite large. Here is some information on them (unfortunately it looks like they have gathered their info from Wiki!).
Anyway, if anyone's planning on visiting Australia you need to know about the flies. We have plenty!