As far as one sci-fi television show or movie "stealing" from another goes, I think there are only so many ways to make up aliens, ships, costumes, helmets, whatever. I have heard people say the Breen helmets look to much like Star Wars helmets, or now the Goa'uld are "bad trill". Well, how would you differentiate one symbiote from another? If an alien lives inside a person, then the comparison can always be made. If from time to time a ship design looks similar to that of another show or movie, so what? People do have influences in their lives and Trek and Wars will be two of the largest when it comes to sci-fi. Lucas himself was a Trek fan before making wars. He took many of the elements from fantasy type books and applied to them sci-fi. Was that stealing?
To secure the peace is to prepare for war. -Metallica