Firstly, they are a very diverse group in many countries, not the James Bond style villains with OBL
as a sort of Dr Evil mastermind as portrayed by the lazy, dumbed down media.
Basically, they seem to want a 'Islam Nation', free of the 'corruption' of the West, with an austere form of theocratic government.
While the US presence in Saudi may have been a rallying point, as well as the plight of the Palestinians, the core of what they want seems to be a revival of what they perceive of an Islamic golden age, before they were pushed back at the gates of Vienna 100's of years ago.
What they don't want is the freedoms of the West, forget what many commentators have said since Sept 11th, they don't give a flying one about having more shopping malls, consumer products and all the rest, thinking that is to be in denial, denial about the mistakes that allowed the US to target the most extreme Muslims for aid in fighting the USSR
in Afghanistan, Reagan called these people, including a young OBL
, 'new founding fathers'.
Why hit Bali? The club was full of Brits and Aussies, Indonesia is way too pro-western for them, so destabilize that nation too, well as a large body count was the intended effect, as were attacks against Europeans in places like Tunisia.
They thrive and recruit wherever they think Muslims are oppressed, be it Palestine, Checnya, Africa, Saudi Arabia, Indonesia, the Philippines, even Iraq under Saddam and now the US.