Favorite hero from Dungeon.

Railag is definitely in a league of his own... :) ... the poisoner Letos is optimal as a support hero - he mines twice as fast as a regular miner (his dark magic isn't really useful, but if you level up "Master of Pain" > "Curse" early on, it's quite amusing). But lately, I've been taking Eruina as my main hero (supporting magic with witches) - she has two good skills right away (Chaos and Attack). Until I build the Halls of Twilight, I send Letos around :D.
And I really enjoy leveling up Eruina - she always gets the skills I need, and a ballista with 3 shots and fire damage seems pretty cool to me) :p
And of course, the choice of hero depends a lot on the tactics.