What are your favorite troops?

[Sir Whiskers]

Early game:

Griffins (great initiative, speed, flight, unlimited retaliation, good hit points)
Royal Snakes (tough, hit hard, no retailiation, two-hex range strike)
Inquisitors (two great abilities - rage, resurrection)
Evil Beholders (good ranged attack, hypnotize)
Dwarven Cannoneers (ranged attack does extra damage to structures)

Once I can get them, I'll swap out the snakes for Orc Shamans (totem, tough melee unit), keeping the snakes in reserve, so I can swap them back in at need.

Later on I try to swap the Dwarven Cannoneers for Elves or Hunters. And I'll often swap the Griffins for Horsemen. I haven't made it any further, so I can't comment on late game units.

If you want to go with undead, I recommend Skeleton Archers (if you don't mind taking lots of losses before you have Time Back), and Vampires (especially Ancient Vampires). Inquisitors don't mind undead, but unfortunately, most of the other good ranged units do, so you'll need Tolerance to add in a good mix of ranged units.

I tend to find most Level 5 units are overpriced for what they give - giants are fun, but at 1,600 leadership each, each one costs the same as 26 royal snakes. Ent are nice, but way too slow. Same with Royal Thorns - a 1 Speed is hard to live with.