An interesting article about the differences between Canadians and Americans from John Ibbitsonhere. It mostly goes over the usual suspects (one of the biggest differences to me, actually, is that Canadians ask this question and Americans don't) but there was one paragraph in particular that arrested my attention:

One of the most perceptive missives pointed out that, while the American Constitution was formed in the age of the European Enlightenment, with its emphasis on individual rights, the British North America Act was crafted almost 100 years later, "at the high noon of 19th-century English liberalism." A utilitarian document, it emphasizes collective good over individual liberty. So a Canadians v. Americans debate is really about 19th-century v. 18th-century liberalism.

Lockean vs. Utilitarian concepts of liberalism, government and property; that actually comes closer to the mark than many (if not most) of the analyses of the differences between the two societies. It certainly explains the differences between the governmental systems and treatment of firearms. It's too bad that Ibbitson had to keep his sources secret, because I'd love to hear more about this theory.