Mahopac will definitely meet your criteria. It has: Blue Ribbon schools, convenient location to regards to transportation/highways, all necessities and shopping nearby, strong community feeling, lots of young families to socialize with, beautiful setting. There is also a synagogue right in the center of town (answering to your previous post). I can't really compare Mahopac to your other choices as I don't know those towns well, hopefully some other people will have insight regarding them.
Feel free to PM me for more specific information on Mahopac. By the way, New York Times published an article on Living in Mahopac few months back. You can check it out at
http://www.nytimes.com/2008/01/20/re...=1&oref=slogin.
Natasha