The thing is plan C type opperations have already gotten al-Queda into trouble at the tactical level in Iraq and Afghanistan. They pissed off enough of the local Muslims that they either started killing them selves or ratted them out the first chance they got.
Also, while the current leadeship in much of Western Europe seems soft their security forces have been nailing terrorists operations before they could be carried out. There is a fair degree of institutional memory from the Red Brigade days and they are starting to change their immigration laws on who they let in and who they let stay.
I’ve noticed that a lot of the Muslim leadership think things will change if Obama is elected POTUS and his party has control of Congress. That Congress want’s to keep their jobs come 2010 and judging by current US polling data that might be a pretty rough job especially if they let everything go pear shaped in Oil producing ME.