On the North Korea front, in 2002, the country offered to end enrichment in exchange for a non-aggression pact. We said no. They made a bomb, granting them an effective non-aggression pact. What would we have lost in acceding to their original demands? Even assuming they broke the pact and secretly enriched uranium, then all that would have happened is...exactly what happened. On the other hand, maybe they wouldn't have. Why was this path better?
Update: Also, the UN is set to confirm the selection of South Korean foreign minister Ban Ki Moon as Kofi Annan's successor. He'll begin on January 1st, and North Korea will, assumedly, remain a massive issue. I don't know if having a South Korean leading the UN will effect the body's action on North Korea, but it certainly seems possible.
Update 2: Or maybe it's the other way around?
James Kelly, the former U.S. assistant secretary of state for East Asian and Pacific affairs, said Ban's successful campaign for the top U.N. job may have played a role in the timing of North Korea's reported nuclear test. Pyongyang has long resented its southern neighbor's power and prosperity and may have been looking to overshadow Ban's election, Kelly said.
On the other hand, I seem to remember reading that the launch coincided with the anniversary of Kim Jong Il's ascendance to the throne. So who knows.