Ask HN: What's your preferred development stack?

Just about every day a new Javascript framework emerges, or a responsive design framework, or a new programming language. Each one has its own hype and various companies jump on and off the bandwagon (GO and Dart comes to mind right away). Trying to keep track and trying to learn them all would drive me nuts. I'm more interested in finding something new, stable and fun to learn. I'm a traditional front-end guy (HTML. CSS, JS), but have started to do more server sided work with Javascript frameworks. I'm also getting into .Net and MVC4. What would you recommend I look at next? Also, any advice would greatly be appreciated as well. This could be links, books, or any resources you think would help. Thanks in advance for your advice! Pete