Here we go, in no particular order.
- Live Wallpapers
- Air Drop (maybe not in implementation but clearly taken from Android Beam)
- Semi-Transparent "Pop-ups" (Notifications, settings, etc.)
- Notifications on Lock Screen
- Settings from a swipe gesture on any screen.
- Multitasking across all apps
- Unlimited browser tabs (more than 8)
- Passwords and activity carried over from desktop browser (Android / Chrome)
- (Some features) Auto-tagging / organization of photos (from Google+)
- App Store auto updating apps
- Did I miss any??
