Fanatic is definately #1 or #2, but the rider is far more crucial as one of the only units that can take out magicians and changlings. Without having long range, most armies are useless (witch, wizard, warlock, necromancer, etc).
Skin walker is definately very powerful too, but again this thead is asking the most useful, not what is the best $50 unit vs other $50.
Skin walker is definately very powerful too, but again this thead is asking the most useful, not what is the best $50 unit vs other $50.