My first thought would be Magni Bronzebeard (before he turned to diamond obviously). Because dwarves are awesome, and he's one of the most badass of them. Of course, that really just means a dwarf that's slightly bigger than the others.
I guess if I want something a little more unique, I'd go for one of those crazy fel orcs like Gurtogg Bloodboil. Anything that makes a badass looking fury warrior would work.