Bootstrap has just been updated to 2.1.0, and one of the most obvious changes is the new white navbar. For those who prefer the old, fear not: you can bring it back by adding the .navbar-inverse class.
The Bootswatch themes haven’t retired their navbars yet, but with the latest update, they introduce alternate navbars. Simply add the same .navbar-inverse class your navbar to try on a new look! Check out the screenshot below, or view them live.

Other major changes that 2.1.0 brings include submenus, an affix JS plugin, and a larger default font-size. You can read all about the changes on the Bootstrap blog.
Or visit Bootswatch to see all of the new navbars.