With truecrypt you can also create file containers, which you can easily backup as a whole by copying them to another disk. In some situations, this has certain advantages e.g. when upgrading your hard disk. It also provides a way to allow access only to certain parts by distributing your documents over several containers. I use truecrypt on my netbook and haven't had any problems with it in years and found it a convenient way to securely share files between computers with different OSes. Truecrypt is also available for linux but unfortunately there doesn't seem to be an ARM/android version available. On linux, I use encryptfs though.