An interesting thought... Ipod was not the first mp3 player, far from it, they just brought the easiest to use package to the personal mp3 player world. Iphone was not the first smart phone, again it looks like they are bringing the ease of use to multimedia oriented smart phones.
I think the next big thing could be Apple tackling the car convergence device...take a GPS/maps director, a mobile phone, an mp3 player for the car with large storage capabilities and maybe even internet, sat tv/radio options and put a killer UI on it that is safe to use while driving (obviously TV/internet for passengers only) and you could have another huge hit. It wouldn't be anything new, as you have all those pieces already, but do you have them altogether with a simple and safe UI? There is a market there methinks.