Yes, Winter' 16 is here and this time salesforce mostly focussed on lauching their new & intelligent UI with Lightning hence making good user experience. It does not support everything right now hence there is an option to go back to Salesforce Classic UI. By going through different objects, you will see that it jumps to classic view automatically for non supportive objects/feature.
UI is cool & easy to use though it will take some time to get used to it. Below are some screenshots for this:
Enable Lightning UI
You just need to enable it from a Quick link 'Lightning Experience' in Sidebar:
Open new Lightning UI
A beautiful loading page will open when you open Lightning UI through link under your name.
A home page will load with some dashboards & assistant with cool tabs at the left.
Pages(Account page in this example) will look like below:
Help for any page
Salesforce removes all elements releated to standard objects from sidebar and added them to Object Manager which will take care of all layouts, fields, recordTypes etc. for all standard & custom objects.
Going back to Salesforce Classic
To know more about lightning experience/UI, go through Winter' 16 release notes.