All depends mate, if your going for a job then I would choose a field that your happy with and concentrate on that, but saying that thers no bad thing in learning as much as you can.

I can pretty much get about in most things in maya, (modeling, texturing, rigging, animating, fluids, dynamics, lighting, MEL and rendering, though a few of em I can just about get by and some of them and would never get a job in!) most of it has been learned as a requirement to creating a finished work and/or curiosity.

Suppose what I'm sort of saying is dont put all your eggs in one basket, keep searching and learning and find out where your 3d heart lies! but then keep a grasp of the rest of it.