But maybe just replace it with a tie fighter or something, because I don't think you can say they put it there just because they could, it gives an impression of realism when you have things moving outside. I just watched ESB on an HD projector yesterday (my room-mate's got one and it's totally awesome and it's kinda sad though, that it's the closest to a cinematic experience of STAR WARS I ever got) and I was so sucked in by the Executor reveal and the scene that follows. I felt like I was in space and I thought that exactly at the moment Vader's looking out in space and there are the massive stardestroyers and smaller ships flying around, it's awesome. God I love these films!