A number of Google properties are getting a redesign. The new designs are a little more sleeker than previous versions and make Google look a little more modern in terms of the interface that millions of people use. To get a look of which way Google is headed in the designs, look at Google search, Adsense, Analytics, Docs as well as Google+ to get a glimpse of how things look.
The image below shows a leaked shot of what Gmail will look like when it gets a new design. The video showing the new design was uploaded by Google to Youtube and for the few minutes it was online (before being pulled), it also showed a number of new features.