Sorry to bump on older thread, but in my opinion, the 'benefits' of a private school do not outweigh the cost comparisons between private and state schools.
With private schools, a lot of the term payments automatically cover features and cirricula that your kid may not necessarily be partaking in.
With public schools, the majority of these options are still available, you just need to pay for it seperately from the school fees.
My son's high school fees for his state school are $550 a year, which you don't even need to pay unless you wish to.
I'd avoid the private schools unless you're exceedingly wealthy.