I personally do think there will be. And as far as this "war on terrorism" goes it might lead to WW3. I want to know what you guys/girls know. And keep to the rules.
In my opinion world war 3 will not occur until Jesus returns, because our technology now would leave everything desolate and leave the ground radiated killing off even the few survivors that are left.
Of course they'll have a WW3, maybe in 50 years, maybe in 100 years, maybe much more, but the History of the world if full of war, so it will occure on day or another... War is in the human nature... Maybe it won't be called WW, maybe we'll fight aliens, or maybe we'll bring war to another planet, but humanity won't stop fighting in 50 years...
There will always be war if human kind exists. a good example is in the game Fallout 3, they say that war never changes, and that is tru. Everything that happened, will happend again. if it didnt happend for a long time... it will happend again soon.
Eventually yes, there will be another world wide war. It's inevidible. As for it being or terrorism and the war in iraq, I don't think it will go that far as to involve the world's most prominent nations. It could escalate to a bigger war, but I doubt it will draw any other nation in.