I'd say Pakistan is the bigger danger when it comes to unstable realms and nukes, seeing as Pakistan definately has nuclear missiles already.
However, Pakistan is a US ally in the so-called "War on Terror" (or whatever they are caling it today) and it is off the media radar in respect to its nuclear arsenal falling into even more extreme hands than it already is. If I had to pick the most likley spot for a nulcear war, Pakistan Vs. India would be it. Small varmints, if you will.
I always believed from that the neocons brought Bush Jr. to power but made sure Cheney was there to run things. Bush Sr. was never one of those neocons and was kept on the outside until the '06 election disaster. Bush Sr. and his allies like Jim Baker forced their way in and have pushed Cheney aside for all intents and purposes.
Regarding nuclear weapons, I don't see any difference between Pakistan and Iran. They are both highly volatile states with significant internal dissent which is a bad formula for for nuclear weapons.
