One more ambitious and useful JavaScript library: ember.js
Conceptually it is similar to angular.js, and even more "oppinionated".
<script type="text/x-handlebars"> {{outlet}} </script> <script type="text/x-handlebars" id="index"> <h1>People</h1> <ul> {{#each model}} <li>Hello, <b>{{fullName}}</b>!</li> {{/each}} </ul> </script>
Among others, ember's core team includes Yehuda Katz,
known for his involvement with reforming Rails 3.0 for performance,
and excellent book about jQuery...
A brave new world of JavaScript :)