A leaked product demo reveals a few changes Google has in store for Gmail, including a redone action bar, a new conversation display and auto-resizing depending on window size.
According to the demo, the conversation view is getting a an overhaul to better show the details, and profile pictures will start showing up in contacts to help you keep track of who's who. The entire window will also be resize better than it does currently. That said, the video seems to have snuck out a little early, as we're not seeing any changes yet.
A New Look for Gmail [Google Operating System]