Personally I am a bit worried about the world right now. 
of people have nukes now...more than ever before. It used to be fairly "easy" in world politics I think. The US and Soviets had nukes and a few of their allies did and nobody was quite crazy enough to use them post WWII (lets not start that). They had their coalitions and empires to protect and nuclear war was endgame for everyone. Take for instance that Russian fellow who refused to believe what the computers were telling him and refused to trigger a nuclear war. He saved the world.
Now you've got minor powers or countries with almost no conventional power at all that have nukes or are trying to build them in the interests of achieving whatever they want. Instead of the careful balancing act that we had during the cold war...anyone of those minor powers with nukes could be a major problem...they probably don't feel the same restrictions to use one. Some of them are desperate to do something...anything.
The comparison can be made to the start of WWI...but I think its better to look at the comparison to WWII. Depending on who you ask...World War II started in 1939, 1940, and 1941. But I think 
of historians say that you need to go back further. The real start of the war was in 1936 with the Spanish Civil War. Foreign powers were involved on either sides of the conflict...namely the Russians and the Germans (Soviets and Nazi's respectively) and the war was sort of a dull murmer compaired to what came later. So my concern is that we're at that dull murmer stage...the right sort of tipping point could take us into a much nastier scenario.
Well, North Korea aside, I don't think anyone who is likely to have nukes is crazy enough to use them. Not even the laughable "Axis of Evil" is made up of cartoon villains and mad scientists. Name the worst despots you can: Iran, Syria, Libya, Saudi Arabia, Cuba, Burma - none are particularly keen on suicide or starting WW3. So nuclear proliferation isn't too much of an issue to my mind, as long as there are sufficient controls in place to ensure that the stockpiles belonging to nation-states are never under the control of few enough individuals to make it possible to give the nukes to real crazies, who would use them.
Pretty much no nation is likely to use nuclear weapons. Even most insurgent groups aren't that stupid. A nuclear-armed Hezbollah is not, I think, something intolerable. But like I said, there are notable exceptions. North Korea, who's leadership is just nuts. Maybe al-Queda (probably not the Taliban, though I wouldn't risk it). It takes a special degree of fanatacism to use nuclear weapons, fanatacism which the vast majority of people, regardless of their political convicitions simply do not posses.
North Korea the way I see it is like a poor, illiterate Nazi Germany, except given decades to achieve their indoctrination objectives and without the moderating influence of an educated, rational top leadership (meaning Hitler's immediate subordinates, not Hitler). The government is a wild card, and even so they still probably would never commit to using nuclear weapons. The greatest immediate danger is probably a coup in Pakistan during which some fringe Islamist groups would get their hands on Pakistan's nuclear arsenal. So Musharraf is a necessary evil, but he seems like a nice guy (see Daily Show)
