If somebody steals my laptop and it's still open, they still have to provide my user password since the screen gets locked after some time of inactivity. And reading from the hard-drive directly won't help, because I got an encrypted hard-drive (with dmcrypt).

I did this precisely because the laptop is a single point of failure. Steal somebody's laptop and bam, you've got access to everything important to that person.

My Android phone is also encrypted (with a much weaker password) and I can also remotely delete everything on it through Google Apps.