If you are using the LESS or SASS Version of the Bootstrap. The most efficient way is to change the variable name, in the LESS or SASS file.
$navbar-default-color: #FFFFFF !default;
$navbar-default-bg: #36669d !default;
$navbar-default-border: $navbar-default-bg !default;
This by far the most easiest and the most efficient way to change the Bootstraps Navbar. You need not write overrides, and the code remains clean.