bin Laden clearly stated his goals in past interviews: remove American influence from the Middle East, destroy Israel, and (by removing his perceived impediments to power) then obliterate the "Westernized" governments in "Muslim" countries including the House Of Saud.
In so doing, the Ummah will then arise and convert everywhere from Morroco to Indonesia to a new Muslim caliphate, in a new world best modeled by the Taliban.
But what's clear is that Islamist militants have become psychologically demented by their ongoing participation in wars (e.g., Chechnya, Palestine, Kashmir, Afghanistan and the Soviets), and have fully-integrated their resulting diseased bloodlust as a (twisted and evil) manfestation of "the joys of jihad."
Should they ever gain power, the Islamists would not settle down to a rational form of government. They would exercise that incipient bloodlust in an even more unrestrained fashion in the service of "jihad". History provides many recent models where bloodlust supercedes the original fanatical ideal, including Pol Pot, Hitler, Mao, and more to the point, the Taliban.
The above article is correct in stating that we can't quite get to the heart of what drives these murderers. But the reason for that is that the Islamists (including the Palestineans) have been made completely insane by their practice and support of murder, death, torture, and savagery. No one can understand insanity but the insane.
Since they have so removed themselves from the scope of rational, civilized society - and they can no longer be dealt with except on the savage level they've sunken to - then the only solution is that they must be killed.