Just finished watching the launch of the New Salesforce.
A new Lightning based interface will be available with the Winter '16 release.
It has the look and feel of the Salesforce1 UI as it is built around Lightning components.
A lot of thought and development effort has gone into improving productivity and making the user experience smoother.
Navigation across objects changes from tabs to a SF1 style sidebar and there are more customisation options for the home page.
Opportunities focus on sales stages and activities. A timeline shows the activities that have taken place on an opportunity whilst the Opportunity Workspace displays opportunities as cards arranged in columns based on stage so you can view all opportunities by stage and drag the cards between columns to change stage.
Reports and dashboards have also had a major overhaul. Dashboards can now contain more than 3 columns and rows don't all have to contain the same number of columns. The look of the components has been brought up to date and also includes animations.
You can choose whether to enable it or not and roll it out to users based on profile or permission set. Salesforce will continue to support the Classic, i.e. current, interface.
The beauty of the Salesforce platform is that customisations to existing systems will carry through to the new interface. There was however a comment that all Visualforce pages should be tested in the new interface to confirm that they work as intended.
Trailhead has a new Lightning module to help prepare for this, have a look at trailhead.salesforce.com.
Can't wait to get my hands on this. Previews are available in sandbox and the new interface will be available in production with the Winter'16 release. Check out the release schedule for your instance at trust.salesforce.com.