iPad. An Apple patent application released today describes a facial recognition system that requires minimal computing power, and works whether you're indoors or out -- we don't use our tablets and phones in a photo booth, after all. The technology works by comparing a current image of your mug to a reference model user profile made using "high information" portions of the human face, like eyes and mouths. Translation: it'll take a picture, compare it against the pictures associated with various user accounts on the device and decide if the two images are similar enough to grant you access. Because this is just an application, it's safe to say we won't be seeing this kind of facial recognition in iOS anytime soon, but let's hope it works better than the ICS version if it does.
Update: An important thing to note is that Apple applied for this patent long before Android's Face Unlock debuted a few months back. The paperwork was first submitted on June 29th, 2010 -- it's just now being disclosed to the public.