I didn't read everything, but here is the list of things I can think off the top of my head.
MMS - Not really for sending, but receiving. I have a lot of people that still send them to me and I never receive.
Email - Being able to attach photos (multiple ones) from the email app
Copy/Paste - Don't really use it that much, but why not!
Push Notification - I would rather push over background processes. In fact, I don't think Apple will ever do background processes especially after the "push notification" segment they had clowning the task manager on winslow.
Turn by Turn - With voice. I love my AT&T Navigator and would love this on the iPhone.
Battery - increased battery life
Today Screen - like Intelliscreen, this would be awesome.