This one comes from the Patent Office, Department of Obvious Things that Seem Like a Must-Have, Office of iPhone OS 4.0 Potential Features: Apple thinks that adding contacts to the iPhone's home screen is a great idea. I wholeheartedly agree.
The contact icon won't only bring contact information. It would be able to do much more:
The icon can also be used to invoke one or more applications that are personalized to the contact. The icon can be modified to display information related to the contact. In one aspect, an icon associated with an entity can be temporarily displayed on the mobile device based on the proximity of the mobile device to the entity.
Anything that could save a click seems good to me. [Redmond Pie]