Recover private keys
Sometimes machines give up on you this can cause loss of coins. Here's a start at an overview of how to recover private keys. If you're reading this just because you might go ahead and make some quick safe backups of your keys.
If your OS fails booting it's probably best to boot from a USB key. After that you can probably find your way since you're a linux geek anyway. If not, try some of the following:
find /|grep wallet.dat # this takes time
Just boot from a Linux live key and refer to the Linux section
Not sure. You were using Time Machine, right? Otherwise, check the Linux section.