Push could do a lot lot more
Seth Weintraub makes a decent point in his September 8 article:
"Why did Apple pull iPhone 2.1's push notification?"
Push could be used for a lot of things - Instant messaging in the background is just one. If they were to ramp it up, and be able to take quite a high number of push notifications per user- you could use this as part of many other areas presumably.
Common sense he says dictates push was pulled because Apple wasn't sure it could be stable by the time 2.1 was final.
What if push was getting incorporated into something more? Push could be used as part of the genius recommendation system. or information of your location if you wanted it. Push used in SatNav.
With an iPhone/Touch fitness app push not yet under way, i'd have thought they would have something out by Christmas also.
You could also take iphone Bonjour, and use push locally - head to head racing via a sport app, using excercise machine data...
APart from push, it seems Apple could do a fair bit, and with Zune's offering, hopefully Apple can match it at least. 2.1 for today?