The greatest threat is from anything that the CIA can get their hands on.
Most terrorism is conducted by the secret services, primarily CIA/MI6/Mossad/ISI, who between them are responsible for 9/11, 7/7, Madrid train bombing, Bali bombing, Mumbai train bombing, Lockerbie air disaster, and loads more.
What the war on terrorism is all about is to keep the people frightened enough so that they give up their freedoms in exchange for ill-perceived security.
The idea of terrorism is to promote the agenda of the Illuminati/New World Order, who control the governments, and their secret services. That agenda is to take control of the entire world, remove over half the population, and reduce the freedoms of the remainder to the levels of slavery
An Illuminati Primer
http://www.rinf.com/news/nov05/illuminati.html
Rothschild/Rockefeller
The Architecture of Modern Political Power
http://dgwa1.fortunecity.com/fourthreich/rockroth.html