We could list lots of languages here (we have) that we could write in, but really that should be a later choice in the software development life-cycle.
Our first step is just one question:
What is the most difficult, annoying or painful thing in your business that needs to be made easier?
From this question we can drill down into what the best solution is, and what technologies are required.
We take on all types of projects, not just creating new software, but also maintaining and upgrading old legacy systems including asp and vb6.