I see several areas of potential conflict, but I'm not sure which, if any, would develop into a major world conflict.
With the decline of the UK, Argentina may be tempted to - and succeed in - taking the Falklands back in the next decade or so. It's something I would certainly not rule out of the realm of possibilities.
Tons of stuff in Africa, but nothing of the major war stuff, unless perhaps it involved Nigeria, Kenya, or Tanzania. But even then, it would be a broader regional conflict, not a world war.
Moving east, there is the chance that 1)Iran will try and seize Bahrain (it has labeled it as a province in some statements) 2) Turkey and Iran will go to war over posturing and influence or 3) Israel and a newer, more Islamic Egypt or Syria will come into conflict. Still, of all these situations, I don't think any will spread beyond the region.
Nothing I can think of located in Europe or Russia.
Lots of potential of a conflict with India and Pakistan (started by the Pakistanis) with Pakistan's closer ties to India, and how India is going to start eclipsing China in the next 2 or 3 decades. Fear, sectarian, religious, and cultural divisions all make this more than likely. This is my #1 choice if there was a war. Pakistan would start it. The Osama bin Laden raid made them very, very afraid (or so my IR professor who just came back from Afghanistan says). They looked at that and said "Oh shit, what if India does that" and more importantly "Oh shit, next time that could be a raid on our nuclear launch sites" So right now, Pakistan is my biggest bet.
Farther to the east, we have China...now as much as China postures for war, I don't think they want it. Well, nobody wants war, but the Chinese are not the type to go to war lightly. If they did, my bets are that it would either be in the South China Sea against a US-led NATO coalition and several SE Asian states or it would be in the west against India. They'd let North Korea hang if Kim Jong Un started anything.