Python is primary tool I have used for last five years. It's nice compromise between speed of development, usability, execution speed, user base and availability of libraries.
When developing for web, Django is currently my primary platform as it's used by our Centrum team.
I belive I learned a lot about development in this language abd am able to design and lead. Check my open-source python projects to check my skills yourself.
Because of long-running projects, I'm still anchored in 2.x series. Hopefully, Unladen Swallow will allow me to jump to the new major line.
I developed some small project in Java. I'm familiar with it's concepts and development, exclusively in SE area (I'm not familiar with ME or EE).
While I'm able and not afraid to use the language to utilize the power of it's libraries, I don't like the language itself and am not interested in developing in it.
I learned C as part of my college studies and created a small project in it later, using CMake, check and other goodies.
I grasped the concepts, learned the basic things and am able to contribute. I have, however, not enough knowledge about dark corners and best practices.
I like the message passing approach to concurrency, upgrades and other goodies. For now, I'm humble apprentice on my path to real-world projects. Together with Haskell, Erlang is now my primary learning target, so I'd like to help and contribute.
When I was young, PHP was the way to program web sites. For a while, I was the eager creator of variety of web sites and PHP was my primary tool.
As I moved on, PHP was covered in dust, as a language, as a techologyand as a concept. I still manage a large site written in it, but I dislike every minute I have to be buried in it's incosistency and missing features. My knowledge is probably also outdated as I do not keep track about current trends, frameworks and stuff.
Originally, I only used that for those tiny snippets to make pages a bit more shiny. Later on, I found myself doing development with YUI 2 and scripting heavily, also utilizing jQuery for smaller sites.
And then, ECMAScript interpreters took the world by storm and are present everywhere (hello, Mongo). I have no choice but to embrace it and use it on regular basis.
Yet I'm not quite comfortable with it I have not yet found the best practices and will reluctantly accept job that would require me to craft something that would sound like a bigger project.