Otherwise, it's "Do it for Bin Laden" , "well yeah but he's dead. I dont think so."
However, to play my own devil's advocate, Islam has a tradition of long memory. I believe Al-Quada picked September 11th because that was the day that construction began on the Pentagon: september 11, 1941, 50 years to the day. The sunnis and the shi'ites hate each other over one little massacre that happened over a thousand years ago ( i believe it was than long ago, not totally sure on the date)
Okay, totally rambling, upshot of message is, Bin Laden the legend who continues to evade the infidels and thumbs his noses at them is more powerful than a dead Bin Laden the martyr.