And for those on linux.. (Score 5, Informative)

If you don't already know about this, and your eyes are glittering with the prospect of encrypted home directories.. there is a way to do this in linux also. It's called the cryptoloop. This is a kernel loop extension that uses the CryptoAPI encryption options to create an encrypted loop of a mount for your system. Although I don't think there is anything to make it as automagic as they probably have set up in OSX, this is something that's out there for those of us that are ultra paranoid. You can visit the CryptoAPI site here where you can get everything you need, or look into the new 2.6 test kernels that have cryptoloop and the CryptoAPI options as a standard feature.