Also on the rear plate, you'll find a fingerprint scanner for a touch more security than a simple PIN provides (and a lot more than the gimmicky faceunlock).
Another interesting -- if perhaps somewhat gimmicky -- new feature is faceunlock, which unlocks the Galaxy Nexus upon recognizing your face (or a picture of your face, as it turns out).
Seven different lock screens are also on the menu, which range from secure options such as FaceUnlock, PIN and password to a rotary style screen that offers up to six apps for quick launch access.