I've always been interested in computer and network security, which is fortunate as I get to do a fair bit at work these days. Recently, I've been looking at personal data encryption, i.e. how I can protect the data on my machines from being compromised, as it sometimes includes customer data that I want to keep private.
The best thing I can do (obviously) is to use a Mac. Both FileVault and encrypted disk images are built-in features and provide robust mechanisms for encrypting data so that it can't be compromised should a machine be stolen.
However, for now, I still use a Windows XP laptop for most of my work (although the move to OS X is imminent :) ) and I also use Linux file servers and workstations. Whilst Windows' EFS is OK, it's not too portable as it only works on Windows, and is difficult to manage in a non-domain environment as it's certificate-based. (Also, if you don't know what you're up to, you can permanently and irrevocably lock yourself out of your own data in some circumstances, even if you know all your passwords).
Recently, I finally got round to trying TrueCrypt as recommended by Steve Gibson on Security Now!, and I have to say, it rocks!
I now have all my important data safe in nicely encrypted files, and can access them on Windows and Linux (OS X support is apparently on the way) using only strong passwords, so if my laptop does go missing, I can rest easy knowing that the customer information on it is safe from prying eyes.