After 9/11, it was 912 days before the next major attack in Madrid on 3/11/2004. Then it was another 14 months before the next attack in London on 7/7/2005. This time, it was 14 days. And it was a second strike in the same location using the same tactics and equipment.
Today, the terrorists (is the BBC calling them "terrorists" yet?) revealed a followup capacity (if not complete competence) that is sobering. Absent some problem with the bomb materials, they would have pulled off a stunning encore.
Today was a near miss, but its lesson is huge. We have to redouble our cooperative efforts among nations to defeat terrorism at its roots but, until then, to defeat it through super-duper cooperative intelligence gathering and military support as needed. These attacks aren't going to stop, and they aren't going to be limited to the geographic boundaries of Britain, Spain, Bali and the United States. And if al-Qaeda gets its way, they won't be limited to conventional weapons.
UPDATE: Read Australian Prime Minister Howard's extemporaneous remarks. They are perfect.