No doubt a Stormtrooper will be cool, but I have liked the last couple of obscure characters (Asajj and T Raider)
I would like to see some bounty Hunters, maybe Bossk, Oola, some Cantina characters or som Jabba Palace charcters...can't think of any off the top of my head.
Or definitely a Death Star Gunner, one of my favorites as a kid.