the first one is good for its attack and speed, and it looks good too)) the second one is good for its survivability and appearance as well)
zombies are also not bad) their survivability is almost as good as dwarves) and I think they look best in the third game, dressed like warriors (upgrade) IMHO))
I also like the lizardman, mainly for its appearance) and it shoots well, if the hero is suitable, or with skills that buff ranged units)
gargoyles are also not bad... they just look bad in the third game (they should be big and strong)