I was reading about it the whole time though (I'm horrible about multitasking like that), and I have to say I'm glad I didn't rush to judgment because the facts changed so much from the beginning story. Initial reports said that the guy was using an "incendiary device" attached to his leg, which wouldn't be likely to do much damage overall (since the inside, and with it his leg, would catch on fire, and no matter how stone-cold the suicide bomber is, a leg on fire will force the body to react). But it turns out that it was just the detonator for a real bomb in his clothes lining, made out of some serious (and apparently easy to acquire) bomb material.
At the same time, of course, it was an utter failure, and as a single attack (rather than the usual redundancies put in place with terrorist attacks) it does make one wonder about the ability of AQ to continue to hit us. Others have pointed out that the physics of this bomb would have led to it not working very well (no shrapnel, no concussive force as the body would absorb most of it, etc.)
I'm not sure what to make of it overall. I think, however, that the best possible point was made by Galrahn at Information Dissemination:
Consider for a moment that even if you add up all the casualties from all the terrorist attacks globally since 9/11, include all deaths related to violence in the Afghanistan and Iraq conflicts, military and civilian, the total combined for the whole decade still falls short of the number of people killed on one day five years ago today.
Yeah. Natural disasters and easily preventable diseases are still a bigger threat to world security (and US security) than all the terrorists in the world. I think that's something we need to remember going forward, especially in an age where AQ can't even blow up a single plane.
PS: Thank you to the passengers and crew of the plane who took it upon themselves to stop the guy and put out the device as soon as they realized what was going on. The willingness to fight back against potential bombers and hijackers in the air is already going to prevent another tragedy using the same techniques as 9/11.