I would be a Ghost Type Gym Leader. I love ghost types so freaking much! So cute!! Here's my team:
Gengar
Chandelure
Sableye
Jellicent
Gourgeist
Trevenant
I'd suggest Dusknoir, The Gripper Pokemon. Not only is it cool-looking, it will be a HUGE pain to Psychic-type Gyms. It's a win-win for you & Dusknoir. You'll kick some butt with him!
I HATE the Fairy type! I do have some of that type in Pokemon X, but I hate it because it's super effective against the Dark type. I freaking love Dark types! SO DAMN CUTE! (Am I the only one who thinks that Dark Pokemon are adorable?)
Mega Darkrai
hp:2809
attack:100
defense:509
Ability is Bad Dreams and Keen Eye
Type:Dark and Ghost
M Darkrai would have blood red spikes all over. It would have multiple creepy eyes. The white thing on its head would become tentacles. The eyes turn red and the pupils purple and like slits.