Garchomp is an Uber. Assuming this is a OU team, he can't use it.
More suggestions: Gliscor. Sand Veil ability. Helps. Especially seeing as he is (surprisingly) more defensively oriented. And I have a friend that rags on about the merits of Rock Polish Aggron. So get one of those too. XD
SR/Dual Screens/Explosion Metagross if you're feeling gimmicky. Nobody Taunts a Metagross, (esp. as a lead) so you can get SR/a screen up, and they still probably won't Taunt after that. Is pretty fun.