TrueCrypt, software known or to be known to keep security about personal informations.
Principe is simple, encrypt our data. Several methods for this: encrypt an entire hard disk (which contains the OS then you will have to enter a password at boot, or contains only data), or a virtual partition saved in a file which will contain all your confidential informations.
A first audit has been done, and it confirms reliability and trust with this software, there is no backdoor inside TrueCrypt! Therefore we can store our data with it, unless you keep your password or private key visible or reachable, no one will access to it, and even under torment (I know your hidden data are so precious, we have to get them!) you have to give your password, you can configure encrypted storage to reveal another storage location with a fake password!
However problems have been found, lack of comments or obsolete functions for example, but really nothing serious about that our data are normally secured.
Stay tuned and to be used (available on every OS).