Well, I guess Star Wars doesn't. Being as we have droids used for war in the PT and for assassinations in the OT.

I can think of many other works that have droids killing people as well. So yeah, I guess there are plenty that don't use the three laws.

Was there ever an indication Lucas actually borrowed these laws? We know it is against Threepio's programing to hurt people, but that seems like just a natural safety feature a responsible manufacturer would put on a droid intended for household use. I personally wouldn't consider adhering to the three laws.