[wizardofmysore]

Couple of things to look for * Language preference * What is present out of the box * How easy it is to extend * Performance

I'd pick one among Django, Rails or one of the popular Js stacks for the backend.

For the front end the same criteria apply, however there is not much scope for language preference. I generally go for jQuery based site unless I have a requirement for a framework. From a framework perspective I liked React + JSX.

I'd say go for JavaScript in the backend too since you'll have to learn the best practices and idioms of a single language.