If your HDD is stolen they can plug it into another computer and copy any file they want.
Likely sitting on an unencrypted /boot, waiting to be replaced by one with a keylogger, am I right? Of course a sane person doesn't trust a system that's been compromised before nuking it and reloading from a clean image.
Though using a USB key for /boot might be an idea, it is a little less clunky than a ThinkPad and since I suspend to RAM most of the time, it could even be practical. Hm.