To be honest with more and more of the UI portion of web apps moving to pure HTML/CSS/JS the back-end choice is becoming less and less relevant. A lot of us are

To be honest with more and more of the UI portion of web apps moving to pure HTML/CSS/JS the back-end choice is becoming less and less relevant. A lot of us are implementing the entirety of the UI in client technologies and utilizing the back end via REST as a service layer. In this architecture, the stack you choose becomes less important because if you decide to swap it out you just start writing new services in the next languadge that you choose. For example I was doing quite a bit of REST services in Java but I just switched over to Clojure and have been implementing new services in Clojure. I could have (almost) just as easily switched over to Ruby or Python if I wanted to. Getting the UI out of the back end stack makes the choice of which stack less of a huge decision because it breaks a great deal of the technology lock in that happens when the UI is locked away in back-end languages. It's not for everybody, but it is something to consider when looking at how the future of the web will be built. The trend of architecting web apps in this fashion is growing as it offers some pretty compelling benefits.