It'll depend on what you want to do - with the huge generalist degree that Commerce is now and the currently oversaturated market of grads, it'd be unwise to do a single Commerce degree with the intention of making it in Business. Not saying that it's impossible, but considering that your competition will be thousands of double degree holders who have made the time for relevant work experience (this is something that I think pretty much
every half decent student has made time for) and extra-curriculars, you will need to prove that your experience is somehow better than these students who have an entire other degree (and an entire line of skills, capabilities and knowledge) on top of you, likely with similar work experience as you.
But if you want to get into Post-grad med, I can't really comment much on this since it's outside of my area of knowledge, but wouldn't a Medical Science degree be a good lead up for that?
I can't seem to find anything on Medical Science at Notre Dame, but from what I can gather from the other unis that offer it is that it's a 3 year undergraduate related to Medicine which you can do in turn with the GAMSAT I suppose to apply for post-grad Med.
B Medical Science, USYD.
B Medical Science, UNSW.
B Medical Science, UTS.
B Medical Science, UWS. (UWS has a fantastic Med department from what I've heard)
B Medical Science, MQ.
Notre Dame seems to have a
Pre-Medicine Certificate which I'm gathering is some sort of accreditation you do during your undergraduate in any degree if you intend to apply for post-graduate medicine. You could do it with the
Biomedical Science degree at ND which I think should be relevant (but again, not really sure, "physio" is in the link so it might not be directly related to medical science like that).
Anyway it looks like you have quite a lot of options so I guess it just depends on whatever you really want to follow.