Toggle between activity feed and fields view
The challenge for most CRMs is how to display the information fields and the activity. Salesforce buries the activity at the bottom of the page in favor of data entry fields (which sucks). Hubspot splits the screen with the fields running down the left side and giving priority to the activity. I like this better, but we use a lot of fields so this still isn't awesome. What would make it awesome would be to split it into two views: 1) contact/company/deal information (fields) and 2) contact/company/deal activity.