PayPal has announced their new Security Key service, which is a small keyfob that displays a code that changes every 30 seconds. After signing up for the $5 (one time) service, you login using your username, password, and whatever code is displayed on the device.
This adds significant security to your PayPal account; even if someone guesses your password, they can't login without the keyfob. And if you loose the keyfob, you still need a password. Many corporations utilize this type of security but very few consumer websites have yet to use a 2nd level of login.