I've seen quite a bit of talk about Palm's notification being superior to Apple's, and I agree. However, Apple already has a subtle notification bar they use regularly, just not for notifications. And it's just as good as Palm's. It currently works throughout the OS (any app that keeps the status bar), unless the application or the user changes to completely full screen. In which case, I'm not sure either notification is the best choice. For example, if I'm playing a game I don't want the edge of the screen which I was tapping to fire a weapon to suddenly become a notification and take me to an incoming SMS. Mock-ups of iPhone with notification bar implemented in Apple's current style... Incoming call, scrolling SMS, and calendar notification.