I've been waiting for this one for years... Meteor.js has finally gotten to the 1.0 threshold and I hope you're like me and looking forward to kicking the tires. I still think this is going to play a major role in the next few years of JS app frameworks.
It's funny that I found this right after I'd already begun basic auth for a product I'm building. Even if it's not quite right as a boilerplate for your next product, at the very least use it as a tutorial.
The React.js community seems to be revving up, and although I'm not as excited about it as other things, I can't deny that the brilliant minds at Facebook are surely onto something special here. So get started with this link, or dabble in the React community on Reddit.