Hardware
iMac Pro in a cool-looking black
Siri
Siri Language Translation
Apple Pay
Person-to-Person payments with Apple Pay and iMessage
Photos
Photos - automatically convert live photo to a long exposure photo (waterfall example)
Maps
Lane guidance in Apple Maps
Malls, airports, floor-level info in Apple Maps
App Store
Great looking new App Store, including new Today tab
AI
Core ML, Vision APIs, etc to make using Machine Learning easy for devs
Amazing demo of ARKit by Wingnut AR that shows an AR game running on top of a table on stage
Other iOS 11 Stuff
Password auto-fill for apps
Screen recording
iOS 11 for iPad
Powerful dock
Split view
Drag ‘n Drop
Notes App
Document scanning with inline handwriting
Handwriting text recognition and searching
HomePod
Smart speaker