At the moment, my primary language of choice is Groovy. Second to that, Java.
If I'm using anything else, it's probably chosen because it's purpose specific in some way (like using Prolog for logic programming or R for statistics, etc.).
We're not really doing anything that uses a desktop UI interface (ie, it's all web based) but I have some ideas for some things we may do later that we might build on top of SWT (Eclipse).