Sydney- USYD, UNSW and UTS. From memory UNSW might be ranked number 1 in commerce in Australia
Melbourne- Monash, University of Melbourne (top notch UNIs)
Canberra- Australian National University (good uni but trust me canberra is the most boring place on earth... no night life whatsoever)
UTS is ok. UNSW, Monash and ANU do actuarial science (insurance basically) which is in severe demand but because of its difficulty not many people pass. Oh wait your planning to do management. I thought u wanted to do insurance risk for some reason...
For management any of the above UNIs are good. Personally i think you should go to USYD for that (in Sydney). The others are quite good though (UTS should be the last option- its a good uni don't get me wrong but it isn't as prestigous as USYD or UNSW). I don't know much about the Melbourne unis. ANU is solid but as i said before its in Canberra (yuck)