If your interests lean more towards traditional statistical analysis and inference as used within industries like manufacturing, finance, and the life sciences, I’d lean towards R. If you’re more interested in machine learning and artificial intelligence applications, I’d lean towards Python. But even that’s not a hard-and-fast rule: R has excellent support for machine learning and deep learning frameworks, and Python is often used for traditional data science applications.
One thing I am quite sure of though: neither Python nor R is inherently better than the other, and arguments on that front are ultimately futile. (Trust me, I’ve been there.) Which is better for any given person depends on a wide variety of factors, and for some, it may even be worthwhile to learn both. Brian Ray recently posted a good overview of the factors that may lead you towards R or Python for data science: their history, the community, performance, third-party support, use cases, and even how to use them together. It’s great food for thought if you’re trying to decide which community to invest in.
Embrace the power of “and.” The whole R versus Python bit is fun for purposes of arguing with people, but they’re both powerful languages and we’re seeing more and more overlap—for example, the Keras package David mentions runs Python’s TensorFlow under the covers.