First-Flash,
Second-copy-paste,
Third-mms,
Fourth-background app capability,
Fifth-Ability to create a "shopping cart" of apps to download and install simultaneously, instead of exiting and reentering the app store every time you choose an app to download.
I know we're supposed to focus on software, but a faster processor would be a nice addition, that would also help with the flash issues.
Also, and I don't see this happening, but I love the resistive touch screens...like I said, I don't see Apple including that, but I personally love them.