Be partial, be biased, wave the pom poms. What features absolutely rock about your favorite tools and make others look primitive by comparison? Bonus points for obscure choices :)
I'd like to do MMO games in js, i'll use Node.js server side maybe with ZeroMQ, and client side it's still a eyes-wide-open https://gist.github.com/749734 , all via CoffeeScript.
Due to massive Not Invented Here, my own framework for node.js (WIN: https://github.com/mathgladiator/win ). I would give reasons for it, but I'm biased.
As to JavaScript, I think it is an end game programming language like C. We are not going to get rid of it for a _VERY_ long time. Fortunately, it has closures so I don't really care.
Any language that doesn't sport closures are simply put inferior.
Apache Wicket is my current choice when it comes to Java and web apps. It makes integrating AJAX functions a piece of cake: for the most part, you just need to call some methods in your Java code. I run apps on Google App Engine with it and am pretty pleased with the performance.
Room for improvement: SEO-wise there is room for making URLs look a bit less ugly.
Ruby192 Rails3
CoffeeScript Backbone.js jQuery qUnit Underscore.js
I'd like to do MMO games in js, i'll use Node.js server side maybe with ZeroMQ, and client side it's still a eyes-wide-open https://gist.github.com/749734 , all via CoffeeScript.