For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
Michael, as usual, provides a good synopsis. I would like to point out that Raikes' Sunday school program has been used by way too many parents to pass off their teaching responsibility to others.
Aside from that aspect, my experience with SS is quite mixed. For instance, I was taking classes in things like algebra and chemistry in high school, but the SS material was on a level more appropriate for grade school.
And I don't think I've attended a SS class that actually dealt with the issues I or my family faced in our culture (which is religion externalized, as Van Til said).
May we also remember - education is one thing...but wisdom is another....wisdom prepares us for life and the ways of life in God's world. A highly educated person is not necessarily a wise person.