I went to private school all the way through. I studied the international baccalaureate in yr 11/12 (not available at state schools) instead of vce, got into my first preference of uni courses and I am now a lawyer.
I imagine if I went to state schools I still would have studied law, although I'm not sure I would have gotten my first choice of uni and I might not have gotten straight in from year 12. For me it was definitely worth my parents' investment (although I had a scholarship so my parents only paid 1/2 fees, they still would have sent me if they had to pay full price).
Private school was about more than just getting into uni/career though. Even if I didn't go to uni, I would still consider it a good investment due to the performing arts program, the languages program, the advanced academic programs, the overseas exchange opportunities, etc.
I will be sending DD to private school for high school no matter what.