Google had an analyst day on October 24th. According too the Google Operating System they didn’t reveal a lot but they did mention what we might see in the new version of gmail.
Prefetching messages
When loading a page with a list of messages on it gmail with go ahead and preload the messages so they load faster when you come to click on them.
A new contact messenger
Yay! Apparently this will be shared across Google Applications (yay! again!)
Application integration
Tying the mail system closer to other Google Applications
There is little information about the new interface, or a release date – Google is keeping that pretty closely wrapped.