Yep, all of that. Numbers work well for zombies and skaven, anything else trick out your heroes instead.
My personal recommendation would be for a small force of Dwarfs, but give all the henchmen helmets. Combined with their race-bonus for hard heads, they just will not stay down when you hit them.
Hired Swords are only useful if they provide something the core group is sorely lacking, like magic or a high ranged skill.