Framework wise, I am loving http://Knockoutjs.com, its an MVVM design style, similar to the pattern frequently used for Silverlight development, and its got great tutorial and support on the site. I particularly like the Knockout mapping plugin as it will automatically map JSON into a ViewModel, sweet!
Checkout the author Steve Sanderson's blog also, well worth reading : http://blog.stevensanderson.com/
I have been getting familiar with http://amplifyjs.com which simplifies ajax request management and client side storage, as well as a publish/subscribe messaging.
Also recently stumbled upon http://xuijs.com/ which I intend to get more familiar with!