Personally, I would say Hitmontop because it gets technician, has good bulk and gets hazard removal. It can also be run both defensively, with intimidate to drop attack on Pokemon like machamp or heracross and rapid spin to remove hazards, or offensively with technician because of its access to priority which is technician boosted.
Defensively
@ Leftovers
Intimidate
252 HP, 200 DEF, 48 Sp. Def (+Def/Sp. Def, -Sp. Atk)
Rapid spin for hazards
Fake out for priority
Mach punch for priority
Pursuit for coverage/trapping
Offensively
@ Choice Band
Technician
252 ATK, 252 Spe
Adamant (+Atk, -Sp. Atk)
Rolling kick
Pursuit
Bullet Punch
Mach Punch