This forum
does make me lol sometimes.
1. Jenny: don't go to a university you feel is your 2nd preference because your friends go there. I can't actually fathom why your friends proximities would sway you that much. You will meet new people, it's ok, and it's not as if you go to Monash that they will disown you and never see you again.
2. Surgeon: Go where you feel at home. If you like Melbourne, go there, but be prepared to know that if the Ivies are your goal, you better be pushing 90+ averages all through your degree. It's doable I think (I'm only first year), but you'll be dedicating your next three years for the goal of getting into medicine. You'll be competing against the best in the world, not just Victoria anymore, and there are some smart cookies out there (not that you aren't bro (? hopefully the right gender)).
Also, why just the Ivies and JH Med? UC SF is top-notch, and so are many others. From what I've heard, it doesn't really matter where you graduate from for med, just as long as your are registered. If you're planning on doing law overseas however, a T14 uni will make your start of your legal career a hell of a lot easier.