I have voted for a public co-ed school for primary school because I believe that good public primary schools have just as much to offer as private ones. I am biased because I am a state primary teacher, but it also makes me aware of the new curriculum initiatives and everything that primary teachers have to go through. Trust me, our public schools have some very good quality teachers going through that care about your kids and do all they can to provide an excellent education. It's also a hell of a lot cheaper!
In saying this, I would love to send my children to a private school (Christian College) during high school. High school is a whole other world to primary school! As far as public high schools go, I think they get a raw deal as to what behaviour they have to put up with when feral teenagers are lumped on them. It is very difficult to expel a child from a public school. I don't want my children having to put up with a nutcase child in his/her class (mind you - my kids could be the nut-case children, ).
Friends of mine that have attended Christian College always seemed so happy with their school and they always looked tidy with nice uniforms (unlike us state-school kids that looked like we had just been hit by a bus most of the time - very untidy). There also seems to be more choice of subjects and more one-on-one with teachers. Children are encouraged to become prefects and hold responsibility in the school. It just seems a much nicer environment for young adults.

Your story was interesting mum4boyz in relation to your son's reading levels. I am not sure how the system works in private schools (and please correct me if I am wrong) but, here in victoria, public schools have to follow a curriculum inititative called "Early Years". It is an intensive literacy and numeracy program that all public schools are expected to follow from prep through to grade 4 (5-9 is called "Middle Years"). There are many strategies used to aid children in reading, writing and numeracy that I have seen first hand, actually work. So perhaps this is something you can all look out for. Ask your child's teacher about Early Years and how he or she practices it. I am still in the very beginning stages of learning how it works, but the children in my class are thriving (most of my "lower" readers are onto levels that are quite sufficient for their educational level atm). I know this only applies to Victoria (the sooner they standardise the education system across the country, the easier it will be for all of us!) but I am sure the other states have the equivalent.