I think philosophy should be a mandatory discipline in high school. Not just training in critical thought, conceptual analysis and logic, but also a basic introduction to the history of philosophy. If you do not understand the basics of philosophical history, you really do not understand the basis of our civilization with our concepts of law, justice and so forth (all concepts which stems from a long philosophical history). A basic understanding of ethical theory would also be good, a high school graduate should be able to offer basic argumentation for an ethical point of view.
Why do I think this should be a part of basic education? Because I think education should be about more than pushing out workers. Education should be about making citizens.
I actually disagree with this. To gain a basic understanding of the history of philosophy would take up a lot of time, and would create a lot of confusion for youngsters. It's way over their heads, and over the heads of many adults, too. And those fundamental questions about the nature of thought and reality are not for everyone.
But the logical and critical thought processes that philosophy uses to structure coherent thinking and ensure reasoned debate would help any student (or adult) to think more clearly, speak more clearly, reason more sensibly, and understand the world around them more fully.
It's not the history of philosophical thought that we want them to know, it's the mechanics of logic, reason, and self-critique.