Communion (1989)

Based on a true story (!) by Whitley Streiber. He and his family come to realise they may have been visited by aliens. This is far from the zap and blast effects of much of this genre and instead takes a subtler, darker and more personal (it's not an alien invasion, more like the personal accounts) approach. In doing this, it becomes much more sinister without being a horror film, there are some truly dark moments. I remember the 'blue doctor' visiting his son very clearly. It has dated somewhat and has its imperfections but in not relying too heavily on special effects, it invites the viewer to share the emotions.