Streets of Fire - A movie that some could consider to be an unknown, but was instramental in shaping anime in the 1980's. Those have have seen Bubblegum Crisis (the original) and it's like will understand exactly what I mean. Also, had some great actors and I could never forget that hybrid era of two rememberable times.
Transformers the Movie (animated) - Don't know about anyone who loved else who loved Transformers G1 at some point or still does, but nothing else really compared for me. It had a great story and had a great soundtrack to boot! Plus I have to say that the special anniversery edition is sweet.
Star Wars (the originals) - These movies were also instramental in shaping my childhood, so I could relate in calling them my favorites. The stories were great, not fantastic, but fun to enjoy.
Tron - This movie was especially instramental in shaping my love for science fiction special effects. Great soundtrack, actors, and graphics to boot!
Super Mario Brothers - I enjoyed this movie, and just to spite the internet community, I am listing it as my favorite. It was ten times better then what most give it credit for. Atleast the princess doesn't have stockholm syndrome in the movie, unlike the one in the video games.