I like almost all heroes, really. I always thought melee-armed heroes in Scifi battles had a great deal of character, like Captain Alexandria (Brittanian hero from ZZD).
As for favorites,
The Dark Lord Lucian (I'd ninja one of FISH!!!'s pictures but they all appear to be broken) was a really cool, versatile hero that worked out well for me in Clash of the Tides.
I also liked Niol from Zahru's battles a lot much for the same reason, those paladin-types are always pretty fun to play. Unfortunately he suffered from Qui-Gon / Sean Bean disease.
And of course, Blaze Ironbreaker is thé badass from Zahru's battles