No one can predict what the landscape will look like in 5 - 10 years. My advice is to look at the tools being used in a field that interests you, and learn thos

No one can predict what the landscape will look like in 5 - 10 years. My advice is to look at the tools being used in a field that interests you, and learn those. Technologies cycle in and out of popularity so you can never be sure what the 'next big thing' will be. But, it's never a waste of time if you learn something that you want to, and you'll be surprised at how often you'll find use cases for your new knowledge. Plus, from my experience, learning any new language/technology makes you better at what you already know - having a new perspective is a very valuable thing. You're an iOS dev, so you're familiar with OOP. Why not learn a functional programming language like Erlang or Haskell? There's a lot of momentum behind FP right now, and both languages can solve problems in different ways than what you're probably used to.