[possibilistic]

1. Rust - Low level systems programming. It has a ways to go, but it is so pleasant to write. In reality this has started to replace my usage of C++.

2. Javascript - Both a scripting language and the Web language. If it weren't the lingua franca of the browser I would much rather choose Python or Ruby instead.

3. Java - A typesafe, managed JVM language perfect for writing microservices, Android apps, etc. For anything bigger than would be appropriate for a scripting language or that must be maintained by several people. Java hits the sweet spot.