The most difficult alternative

For Haven, I always build pikemen, crusaders, and champions (call them knights or paladins, whatever you like). I always run out of resources for archangels. For Stronghold, I build harpies, cyclops, and birdmen (cyclops are definitely stronger than ogres, and there should be at least one ranged unit, but monsters are slow). For Necropolis, I always build one line of units. For Necromancer, I only build undead. For Inferno, I only build demons; honestly, I don't see much difference between them, maybe cerberuses are slightly stronger than ghosts, but overall, I think they're about the same. For Sylvan, it's always difficult for me to choose. If I have tigers and elves, I always choose elves. After that, I start thinking about which units to build. For Chaos, I almost always build medusas, nightmares, and hydras, but sometimes I hesitate between horses and ifrits. And finally, for Haven, I always build mages, djinn, and titans.