TUAW summarizes Mat Honan's night:

They used that access to reset his iCloud password, reset his Gmail password, gain control of his Twitter account (which in turn gave them access to Gizmodo's Twitter feed and 400K followers) and generally wreak mayhem.

Unfortunately, Honan's iCloud account was tied to his iPhone and iPad, which both had Find my iPhone/iPad turned on. In the attackers' hands, the FMI utility was turned against Honan and both devices were remotely wiped. It got worse: his MacBook Air had Find My Mac enabled, which meant the hackers could erase his SSD... and they did.

Ouch.

I've always believed that your email should be they most secure password out of all your accounts. But man, it never occurred to me how much havoc can be caused when someone hacks your iCloud.

Lesson learned.