Alright let's see: The entire user experience. Name one smartphone that came before the iPhone that actually has music-playing capabilities (by that I mean a jukebox like iTunes, not some cheap file browser with a media player), an app store that allows 3rd party developers to contribute, wifi, a 100% touchscreen interface, and an app-centered GUI (as opposed to a set of menus).
Even the iPhone didn't have all those features when it first came out.
If you really want to get technical about it, you could say iOS is an extension of the old PDAs that have been around since, at least, '98. You can clearly see the genesis of iOS and Android by looking everything Palm had released beforehand.
Like a jukebox? I'm sure the Palm Tungsten and it's contemporaries had something similar, which came out around 2003-2005...

Anyway, I could go on and on and on, but I don't want to. It's all the same tired argument that's been repeated 50 billion times previously. I'll shorten it all up by saying...
The iPhone, Android OS, all we're seeing now, are all evolutionary steps on a long road that's been building since the 90's.