i had that same choice as well. But i decided to go to commerce (international) at UNSW, cos they are ranked highly in the business faculty. I suggest if u do end up doing comm/law, you should go towards the law stream and not the commerce side, cos Macq aint that great cos just doing commerce by itself doesnt have any professional recognition. and that going towards the business stream, all the law subjects u choose wont help that much. WHERE AS if you go towards the law stream, the commerce subjects will help a fair bit (ie commercial law).
And so i wanted to go towards business stream so thats why i chose UNSW.
Comm/laww itself is 5 years, and if on the last minute u want to change to business stream, then maybe you can go for CA or CFA, but this would take at least another 3-4 years.
where as commerce, if you work really hard you can graduate in 3 years and then go for CA or CFA or MBA, all in 6 years time, and earn quite a lot of money (CFA and MBA).