Just bcause other nations have the capability of producing chemical weapons doesn't mitigate the Iraqi/Terrorist threat. It isn't a reason to do nothing.
Iraq is a priority threat for three reasons. 1. They have the means to do us harm. 2. They have a desire to us harm (I can site several examples). 3. They believe that they could get away with it. (can also site many examples of why I believe this to be true - remember the asassination attempt on Bush Sr.? Did they fear U.S. retailiation?). Just because a country has the means to do us harm doesn't put them in the same league with Saddam.
Most of your examples deal with chemical weapons. Although chem weapons qualify as WMD, Biological and radiological weapons are more effective, thus much more dangerous. Read the Q&A of Dr. Richard Spertzel from the Nov. '02 House Armed Services committee. Frightening stuff.