Since the keynote, more specifically Scott's iOS section, I have been thinking about Passbook. Apple describes it as "your digital wallet for loyalty cards, Amtrak, United, hotel reservations and more."
So the idea is great, better than squirrelling away random details of cards in notes, or using a third party app. The implementation is beautiful as you would expect, what really looks great is that the details update automatically. What this could mean is, once you have your boarding card for the plane and you have been given your gate details, what happens if your gate number changes? Well Apple demonstrated that when there is a change, you get a notification and the details automatically update.
With location services, if you walked into Starbucks your loyalty card would appear on your iPhone and scan the barcode from your phone, updating your balance too.
NFC (near field communication) style apple payment system? either built from the ground up by Apple or using a partner like Visa? As NFC or contactless payment becomes more wide spread and Android phones market this as a feature, it stands to reason Apple will need to join the party.
On past history, Apple isn't always first with all features; but when they do implement them they are game changers. FaceTime wasn't new, I had 3G video calling when I had a Sony Erricson V800 ages ago. But it wasn't widespread enough or reliable enough or a pleasure to use, Apple made this so.
So collectively lets cross our fingers for a contactless payment solution for iPhone, even if it's just a payment tag for the next new iPhone.