Terran have more weapon/armour upgrades than the other races, actually (names are probably off).
Protoss Air Weapons, Protoss Ground Weapons, Protoss Air Armour, Protoss Ground Armour, Plasma Shields (5)
Zerg Melee Weapons, Zerg Ranged Weapons, Zerg Air Weapons, Zerg Carapace, Zerg Air Carapace (5).
Terran Infantry Weapons, Terran Vehicle Weapons, Terran Air Weapons, Terran Infantry Armour, Terran Vehicle Armour, Terran Air Armour (6).