I like those futuristic way of identifying one-self. I have a friend who have a fingerprint identification on his laptop. I don't really know what is used on BSD system but on Linux people can play around with PAM and create exotic way of identification.
[Face Recognition](https://lwn.net/Articles/523199/) and [here](https://code.google.com/p/pam-face-authentication/)
[Fingerprint Authentication](https://lwn.net/Articles/259363/)
[Smart Cards](http://www.gooze.eu/howto/gnu-linux-smar...pam-pkcs11)
[USB dongle authentication](http://usbauth.delta-xi.net/doku.php)
[Voiceauth](http://code.google.com/p/pam-voice-authentication/)
[Normal USB](http://pamusb.org/)
Adding [captcha](http://www.semicomplete.com/projects/pam_captcha/) and [here](http://www.michaelboman.org/how-to/secur...am-captcha) to PAM

There's just so many ways! It's really interesting.