I love PhaserJS by Photonstorm. One of the best and most complete engine you can get for creating games with HTML5.
I’ve created a Boilerplate Project in February 2014 based on Grunt and a lot of tasks like concat, minimize etc. That’s nice, if you want to create a game to be distributed sometime. For me the setup was to “complicated” when I just want to create a small prototype or proof of concept.