Which race would you add to Heroes?

Well, if dwarves are out of place in an elven castle, then what are centaurs doing there?! Half-human, half-horse creatures have nothing to do with elves, but it would be boring without them, just like without the dwarves.
And why not create a race of aliens, for example? It would be interesting to see how vampires drink green blood and curse about genetic incompatibility.