You have all missed my favourite: Preator Zeratul. He led the cast-offs of his race back to the Protoss homeworld when the entire region (and conceivably, two species) was at the brink of destruction. Gravelly voice, love of the shadows, reluctant undertaking of his role, willingness to think outside the box when forming aliances, psyionic energy blades... was he missing anything at all that could have hindered his greatness or just made him cooler? The moment his obscured visage uttered the words "Mayhap o' Queen..." you knew that the final mission of StarCraft was going to be an absolute barn-stormer, especially when accompanied by the holy trinity of Raynor, Tassadar and Fenix.
Let us not forget the expansion pack either, where he brought us the Dark Templar. They made the Zealots completely redundant, which is fantastic of course as your cannon-fodder unit should never be THAT expensive and time-consuming to build.
To sum up: Hard as nails; cool as ice; solid as a rock; easy to integrate into your army.
Oh, and the SAS/British Armed Forces equivalent of the Medal of Honour is the Victoria Cross.