I think your fraternal/sororial organization ought to be an extention of what you believe in. My ideals and standards about what manhood and brotherhood are -- and what these ideas should push me to do in the community as a result -- are exemplified in my fraternity.
But my energies and desire go well beyond my frat. I work/serve in my church, within my profession, in community service with area youth; these are all key drivers for me. A 100 Black Men chapter recently started in my city. I was asked to join but I declined, not because their efforts aren't laudable but because I'm already involved in similar efforts through other organizations.
And trying to have some semblance of a social life, duplication, I do not need.