What are you the best at doing? What is the thing that rises you above everyone you know? You know what it is; this is your core talent. Yes, you do have a core talent whether you acknowledge it or not. To be successful, everything you do should circle around what you do best.
Over time, being diversified is helpful and wise. Make sure the things you add to your career skills complement your core strength. Too often people diversify with activities that have nothing to do what their inherent skills. This will kill your career.