A melee unit with an halberd, a ring of health, a regeneration armor, and a helmet of fear (plus something else interesting, like bracers...). It's true that it's difficult to assemble such a set, but with this combination and a sufficient number of potions of immortality, along with good control, you can easily defeat enemy mages and melee units. Even without support.
P.S.: It's also useful to drink a potion of double strike and frost - so that when the enemy hero gets up, you don't let him drink that coveted potion.
There is no strength in flesh, only weakness
There is no Constancy in flesh, only decay
There is no certainty in flesh but death
