When Terminator 2 was released in the early 90s, I was truly amazed with CG special effects pertaining to Robert Patrick's T-1000 character. With that being said, my favorite special effects in a great sci-fi movie would have to be Independence Day. I was in awe of the space ships and the relentless doom portrayed by special effects in the movie. I would also have to say, naturally, that the Star Trek & Star Wars movies exhibit spectacular special effects as well.