Just read Ten Things To Do To Secure An Important Persons Computer and it talks, among other things, about using BitLocker (or TrueCrypt) to encrypt your hard-drive.
I have always thought that that could probably be a nice thing to do, but I have never done it because I'm worried what will happen if my computer crashes or if I reinstall/switch my operating system. Will I be able to take out the hard-drive, stick it in a new/different computer and get my data? Or is it lost forever if my motherboard/operating system dies?
How would that work really?