So many people have sent in recommendations, but I think this team is the best: blaziken-sky uppercut, blaze kick, fire blast, double kick shedinja-shadow ball, hyper beam, silver wind and a move of your choice:

manectric-thunderbolt,thunder,quick attack,shockwave
salamence-dragonclaw,fly,flamethrower,dragonrage
golduck-surf,waterfall,blizzard,& a psychic type move
groudon-slash,solar beam,earthquake,fire blast

The best thing is that you can use this team vs. elite 4 just level 55 & above!