I like touch UI, but I don't like the Apple UI. And I don't like embedded eye candy - where selecting an item launches an unavoidable three layer translucent 3D animation that looks pretty but accomplishes nothing.
Hmmm... maybe Bluetooth remote control pod, like Wii remote... so if/when you need hardware buttons just pick that pod in hand and there you go... Great to remote control that MP3-player in pocket while jogging in treadmill...