Well then, Giratina should be going, seeing how this is an OverUsed team. Either that, or a doomed Uber team. Gengar should stay, but Mismagius should go. I would replace Aggron with either Tyranitar or Metagross. Magmortar is fine. However, Arcanine or Typhlosion are better in my opinion. You need a good grass type, and I suggest Breloom. Youalso need a Water type, and I would choose Starmie. Also, Dragonite will round off this team. For movesets, do as Swampert said.
Team: Dragonite/Metagross/Tyranitar, Gengar, Breloom, Starmie, Electivire, Magmortar/Typhlosion/Arcanine