In my daily work / projects I actively use every one of the following :<p><pre><code> Servers - Apache, Nginx
Databases - MySQL, SQlite, Redis
Languages - Bash, C, PHP, Ruby, JavaScript
IDE's - Emacs, Vim
Tools/Frameworks - Git, GCC, GTK, Webkit, Symfony2, jQuery
</code></pre>
These are all things I use to build finished software products, I experiment around with Go and Haskell, but haven't used either much for practical purposes (except Go for a few server side things).