Necropolis is the best! You can breed thousands of skeletal archers (this is about the version before patch 1.5; later they came up with this stupid "dark energy" system). Ghosts can really mess up the enemy's nerves (and army) because they have a 50% chance to miss. Vampires (!) regenerate, and their stats are pretty good. Liches shoot and can cast some nasty spells on the enemy (although they are average wizards). And the other units are generally not bad (only the dragons have weak stats...).
Necropolis is the best! You can breed thousands of skeletal archers (this is about the version before patch 1.5; later they came up with this stupid "dark energy" system). Ghosts can really mess up the enemy's nerves (and army) because they have a 50% chance to miss. Vampires (!) regenerate, and their stats are pretty good. Liches shoot and can cast some nasty spells on the enemy (although they are average wizards). And the other units are generally not bad (only the dragons have weak stats...).