Just to promote a heterodox(ford) opinion: while Torch is great, learning Theano might be a better use of a budding data scientist's time because python is used much more widely in the industry.
I think learning a new language like Lua along with Torch is probably useful if someone is doing cutting edge neural network research.
And to promote an even heterodoxer opinion, learning Deeplearning4j might be an even better use because Java is the language of corporate IT, the language of Hadoop (and therefore big data), and because Spark is based on the JVM. If budding data scientists want their neural networks to scale, they should think about distributed systems from day 1. http://deeplearning4j.org
Full disclosure: I helped create DL4J, and it is a younger framework than both Theano and Torch.
The approach generally taken by Oxford and similar is that a scripting language like Python or Lua is simple enough (or at least the bits of it needed for the course are) that anyone taking the course can pick it up with no specific learning necessary.
I think learning a new language like Lua along with Torch is probably useful if someone is doing cutting edge neural network research.