I am starting to look at the same... and I am going to look at http://fuelphp.com/features , which looks like it has
great features already in it, including authentication.
And if you love javascript, you should check out http://trello.com which was made using a javascript stack and
is described in this blog post http://blog.fogcreek.com/the-trello-tech-stack/ . Looks amazing...