Don't want to bump in too much ^^ . Congratulations on your ATAR
Visiting info days is usually pretty good, they helped me choose which engineering I wanted to do (elec eng).
Generally if you like business etc. you can do commerce, economics and a bunch of other business degrees. To be honest though, you're probably better off not doing commerce as they tend to be generic and a lot of employers seem to NOT regard commerce degrees as highly (feel free to dispute but that's the general vibe among my mates in consultancies and other places). You also learn relatively bludge maths (the hardest thing you do in some first year units is draw a straight line and fit it to some data!) However, Economics seems to be tough but good fun.
Also, don't waste your time doing management courses - they're generally quite boring and generic. Also, Project Management (at least at USYD) is very bludge and my mates doing it say they generally wouldn't do it on its own.
Science and maths are good if you loved science units and maths in high school. You get to really explore what's going on behind the scenes (you also realise how little you know about how things work! Also, a funny thing is that things have come so far in physics, for example, that in the undergraduate you kinda only get into the crazy, fun stuff in your honours (final) year).
Engineering is good if you want to do something both theoretical and practical. It's like a science/maths degree but you apply it to more concrete situations. Also, you generally get jobs if you're decent
. Do this if you liked science and maths in high school. Do note that you don't necessarily stereotypically build stuff all the time but you'll get the chance to - and it's worthwhile!
If you didn't like science and maths in school, do note that the way science and maths is done in school is very different to uni (though it is changing for the better)! In other words, you may like it at uni!
As for arts, I know a lot of people do it generically because they don't know what they want to do. At least from the people I know, if you like reading long passages, asking questions (and learning how to ask questions) and having your mind blown in a philosophical/social sciences way, do this!
** there are some issues with some politically-oriented courses at USYD - just read USYD rants on facebook **
Teaching is also a strong course to take. I've heard mixed things about some of the courses but overall my mates have tended to not regret doing teaching. If you do secondary education you do a double degree with the subject(s) you want to teach so that's fun. You also have basically guaranteed employment for life
As for other degrees I have less knowledge/experience. I've heard good things from my physio mates at ACU. OT, speech path apparently have some dodgy forced practical experience requirements but my mates seem happy (ish).
As for unis, I'd generally pick UNSW and USYD because they have the rep. USYD seems relatively strong in course content and I've heard good things about UNSW generally (minus trimesters!). Campus life is good but you have to invest time into people, societies, being physically present and your studies. I'd avoid any courses with weird majors like humanitarian engineering, Internet of Things major in electrical engineering, .... . Stick to more traditional courses since the teaching material is more established and you have more flexibility.
The tldr: Pick USYD/UNSW if you've got the ATAR for the course. Avoid exotic/new courses, stick to traditional ones. Do Science/maths and/or engineering if you like that kind of content. Arts is a strong choice with heaps of options you can explore. Eco is a good business-related degree that has more challenging maths. Teaching is also a strong choice if you like teaching (hint if you like tutoring, teaching is not a bad option!).
If you're still unsure, you can try a double degree in arts/science or arts/maths and then pick which side you want to go down later. You can also do flexi first year in engineering if you want to do that. Don't forget you can also change your degree later and you're not 100% locked in in first year. This also applies if you want to do a course and you don't have the ATAR- you can pick a related course and then transition later.
Disclosure: I am doing electrical engineering and advanced science (Physics major) at USYD. I'm starting my final year next year. I admit I'm very biased towards doing science and (especially) maths as they are REALLY important, are valued highly by employers and will give you good analytical skills wherever you go. Not doing maths will hurt you later.
Edit: on the surface the campus may not look exciting. Wait until you go into the high-tech labs they have. Also, a lot of excitement is in the society events which happen on and off campus e.g. for engineers we do a lot of pub crawls, engi/science does cruises, other societies go bush-walking/motorbike riding...