After building a few applications, some in Symfony-PHP, some .NET MVC, some ROR, i’ve found that the best way for me is to use Yeoman.io with the AngularJS generator.

That’s the most popular and common structure and best maintained.

And most importantly, by keeping that structure, it helps you separate your client side code and to make it agnostic to the server-side technology (all kinds of different folder structures and different server-side templating engines).

That way you can easily duplicate and reuse yours and others code.

Here it is before grunt build: (but use the yeoman generator, don’t just create it!)

/app
    /scripts
            /controllers
            /directives
            /services
            /filters
            app.js
    /views
    /styles
    /img
    /bower_components
    index.html
bower.json

And after grunt build (concat, uglify, rev, etc…):

    /scripts
        scripts.min.js (all JS concatenated, minified and grunt-rev)
        vendor.min.js  (all bower components concatenated, minified and grunt-rev)
    /views
    /styles
        mergedAndMinified.css  (grunt-cssmin)
    /images
    index.html  (grunt-htmlmin)