[Dario] “and in it he talks about NOT showing that your a ‘jack of all trades’ in your reel.”
That entirely depends on what kind of job you’re applying for. If you are seeking a job as a Flame compositor, there’s not much point showing off your DVD authoring skills. But if you are speaking to a production company who makes TV spots, DVDs and corporate videos, they will almost certainly WANT you to be a jack of all trades.
If you have an extensive range of skills and plan to apply for very diverse jobs, it may pay to cut separate reels which demonstrate specific skills.