Depends on: what your potential research interests are, since both universities have different focuses. Consider logistics. Also consider whether you are fine taking another year to do an MSc at Melbourne (though you can still do honours through the medical school I think).
Is there no honours for U of Melbourne BSc? I was under the impression that there was...
If you mean 'future plans/hopes' by 'research interests', I'd like to do further studies (grad school)/then do research in molecular and cell biology/biochemistry.
Hey, firstly, I love your username lol, it's the name of the theme song to True Tears!

Now to answer your question, I'm not particularly informed in the life sciences area however, just generally, undergraduate degrees (Bsc) are quite similar b/w Monash and UoM in terms of prestige, however if you do intend to continue with honours/masters, it would be better if you do it at UoM, UoM definitely has higher reputation than Monash in higher academia (not sure if this is the case for life sciences though)
This is what I heard from an acquaintance or two, but I'm not too sure how reliable that is...so here I am!
Although I'm an Australian citizen, I come from Hong Kong, so I don't have too much knowledge on Australian universities. :S
It is not for Melbourne; according to several teachers at MHS, Monash is better for chemistry & life sciences.
e: Whether or not that has any credibility with you guys is up to you, but generally the MHS Science faculty is right...
...what's MHS...?
Not that you should ever pay too much attention to 'rankings', but it could be of interest to you that Melbourne is ranked 27th in the world for life sciences, where Monash is not within the top 50 - according to the Times Higher Education rankings, that is.
Not that too much attention should be paid to rankings at all, but this is also corroborated by QS (U Melb 25th, Monash 50+), but I'm not sure how much this matters to an undergraduate program or the difference in prestige.
Is there anything special about a BSc Advanced Honours that's worth passing over a relatively better institution in preparation for graduate school, if Melbourne>Monash is indeed the case?