FileVault is a data protection system that's been around for the past two major OS releases. It uses encrypted file systems that are mounted as a secure disk image when t user logs in, and unmounted when the user logs out. The home folder is encrypted with a key based on your password. Forget the password, and you are pretty sunk. The encryption is AES:
Every file that is created is encrypted (or decrypted if you are opening something) as needed. Your encrypted data is packaged into 8MB chunks instead of one large file.
I have a couple more questions because you might have given me an eloquent way to do this -- buy the mac. use the normal mac os, and simply put in the AES thing.
If i did that, would i be able to operate under that profile without hassle? in other words, if i had a browser for that profile, and vid downloads etc etc, would they all operate normally, keep bookmarks (specific to that profile), keep search histories if i want, keep passwords (probably specific to that profile) and work for a neophyte?