Multitasking as seen in the OS 4.0 presentation, as for the new hardware and software features yet to be revealed:
Front-facing camera, 960x640 industry-leading screen resolution, built in iChat functionality that is integrated with the OS like BBM complete with video chat over 3G, and maybe to handle the new network load; a Verizon iPhone.
AT&T's exclusivity is over, and to be honest, I don't think they want the exclusivity anymore. It's brought them a lot of subscribers, but now that they have them already, they are getting sick and tired of the complaints. If there's an option to be with Verizon, people will have less right to complain and the condition of the network will improve more quickly. It was definitely in AT&T's best interest to acquire exclusivity to the iPhone, but now it is in their best interest to get rid of it.
I am guessing both as well. A unibody iPhone would be nice, like the MacBook Pros. Wireless N. A better camera, don't really need the "front-facing" camera. How many of you actually video chat? or would Skype while walking around the mall, etc.?