What JavaScript Frameworks and Libraries are best suited to cross-platform MMO game development?

I've played a great many MMORTS games such as Evony, Dragons of Atlantis and Kingdoms of Camelot. They all have some great features and a great many not so great problems. Simply for my own interest I wanted to try my hand at writing something similar. I don't intend to even try to compete with the big boys but I wanted to write it in a professional and scalable manner as if it was intended for eventual commercial release.

So that's the background that leads into the question. I have been looking at various frameworks and libraries that would be suited to this style of game. However there is such a plethora of options that my head is now spinning. I would like to get some input as to what other people think are the best options. I want to try and write this as a cross-platform / cross-browser webapp that can later be converted to a "Native" app using something like MoSync. I want to stick with HTML5, CSS3 and JavaScript technology.

Some of the things I am sure I want are:

• It must be scalable (ie able to handle a significant number of simultaneous users)
• I prefer to work with some sort of MVC framework (I am used to working with Joomla MVC and have been considering backbone.js for this aspect)
• I am no JavaScript guru but will most likely want to work with jQuery (mostly in relation to client side views)
• I like templates but am completely lost which template system to go with (ie mustache, handlebars, dust etc). I think my choice in this area will ultimately come down to which framework I end up with.
• Chat is an important aspect of MMORTS games and I am thinking of using Node.JS and Socket.io (or NowJS) for this.
• I have also been looking at Redis for key-value store.
• At this stage I have abandoned the idea of using jQuery Mobile as initial tests have caused more headaches than they have solved.

So my front runners are Node.JS for server side JavaScript (possibly with NowJS to implement chat), Redis for key-value store, backbone.js for the MVC framework, mustache (or maybe LinkedIns fork of dust) for templating and Jquery of course.

I would greatly appreciate any input to help me make my final decision on what frameworks and libraries to use.