I was looking at a few contacts and wanted to find email I sent to them. I then thought about a feature in Gmail that listed all email with a given contact. This would be a perfect view off the contact's dialog. I want to be able to see any and all collaboration points with the contact, so show me email, appointments, and tasks. Hell, I'd even like to see how each contact is related to other contacts. Contact relationships might be a bit harder to visualize, but I can think of a few ideas that should work fairly well.