Palm has a stellar, non-interuptive, non-"choose it or lose it" notification system, and according to our sibling site PreCentral.net, the man who designed webOS notifications has left for Apple:
The man who "Invented the non-intrusive banner notification system used in webOS" and also did all sorts of other work for the OS, Rich Dellinger, is leaving Palm to return to his earlier employer, Apple, as a Senior User Interface Designer.
Does this mean iOS 4.x or iOS 5 will be getting better notifications? They've likely been working on that long before now, and who knows what Dellinger will be assigned to, but since notifications remain one of the few sore sports in iOS, we're very much hoping it does and the sooner the better.
And let's top that off by asking what kind of notification system you want to see in iOS? Palm and Android both do it well, how could Apple do it better? Simpler?