- If you want to do JD, I recommend Arts, or Commerce, as they are more languagey/humanities-y courses compared to say, science/music/biomedicine. This will prepare you better for a law degree. I don't know what environments entails so can't help you there.
- I have seen several law firms advertising for students to do internships, who only wants commerce/law, accounting/law, business/law (etc.) students. So if you want to get into corporate law, a commerce degree would be best.
- If you get a high enough ENTER to get into law/xx at Monash (which I think now is ~98), TAKE THIS OPTION UNLESS THERE IS A REALLY GOOD REASON NOT TO GO TO MONASH. Like someone above said, you'd be pretty stupid to (unless you're happy with the possibility of ending up with just an undergraduate degree if you don't get into JD). And it's not just UoM - JD at Monash is pretty damn competitive too.