Greninja/Trevenant/Heatran core (once pokebank is out obviously)
Greninja will run Spikes, Trevenant will spinblock and have Forests Curse to make Ice Beam/Lava Plume SE against EVERYTHING, and Heatran covers their weaknesses.
Then I'll use Togekiss/MegaAbsol/Alakazam as the rest.
Alakazam is mainly for revenge kills, and the other two are more for late game, Togekiss and bulk it's way through with flinches and roost, and Absol can overpower whatever remains.
Alakazam was mainly chosen as I lacked a Psychic type, Latios is another option if that would be better. Absol was chosen pretty much cos I lacked a mega and Absol seems cool, dunno if say, Kangaskhan or Scizor or something would be better. --- [This signature was deleted at the request of the La Li Lu Le Lo]