One important thing to point out is that you will be studying Engineering. Whilst it may be beneficial to take notes on a laptop in Biomed (a few of my friends do this), in Engineering there will be a lot of formulae taken so writing these notes is, as you can imagine, far more practical.
I studied BIS (which is basically IT combined with Business) last year, and although I took my laptop with me on a daily basis it was not needed. Monash has wireless internet, so often you will find yourself being distracted and surfing the net throughout lectures, as opposed to being the diligent student which takes note of everything the lecturer says.
A laptop is REALLY great for finishing assignments at university, for two main reasons. One, you can seek guidance from your fellow students. Two, a lot of the time computers are either taken, or not easily accessible.
As CatOnAHorse stated, laptops are not a requirement for university life, and by no means will you be disadvantaged in any way for not owning one (I believe the cons and pro's of owning a laptop cancel each other out).
It would be most beneficial to you try uni life without a laptop and if you feel in anyway disadvantaged, then purchase one. If money is an issue, I believe there are several companies that loan laptops for $15 a week or so, so trialing this would be a safe option in ascertaining whether it is a viable option for you.
Hope this helps =)