Robes, cloaks, and capes are excellent garments for villains. Where would Dracula be without his cape? Or Xykon? Or the Evil Queen from Snow White? Or old, overweight Elvis?
If your heroes start pimping up by wearing a cape or a cloak, however, make sure it gets caught in any handy machinery that happens to be anywhere in the vicinity. Jet engines, escalators, soft-serve ice cream machines, rice threshers, whatever.
GM: As the smoke of battle clears, a towering dark figure in black armour and a black helmet strides in.
R2-D2: Whoa. Who the heck is this?
GM: His face is hidden by a gleaming black mask. His breathing echoes heavily through the corridor.
GM: He pauses to inspect the bodies of the Rebel soldiers his troopers have efficiently killed.
GM: Black gloves, black boots, and flowing black robes complete his attire.
Captain Antilles: Do you think this might be a bad guy?
R2-D2: Hmmm... Hard to say.
Captain Antilles: Yeah, if only we could see his facial hair.