I've always been a strong advocate of people having hobbies outside of coding. For me it's music, for others I've known it has been anything from crochet to climbing.
Personally I find it helpful to be able to switch off, unwind, and think about something different for a while. Equally it's something else to talk about outside of tech (particularly with clients), and, on one occasion, something actually came in use during a project.
So, is it important to have a hobby that isn't coding?