Right, so I had to really think about this, and most of these films are my introduction to the characters or series but the first film I'd take with me would be the 1998 Godzilla movie. I know this has a reputation as being one of the worst films in the Godzilla series (so much so that the studio that made the original Godzilla films doesn't consider the creature in this one Godzilla at all) but it was the first giant monster movie I ever watched and I have been a fan of Godzilla ever since.
The next film would be The Road to El Dorado. This was one of the films I watched over and over again during my childhood. I loved the soundtrack to it and just thought it was a very funny and enjoyable movie.
The third film would be the 1996 Doctor Who movie. This was the first classic Who adventure I watched and it introduced Paul McGann as the Doctor. Unfortunately, it wasn't successful enough to give McGann his own series as the Doctor but it is still a brilliant film and gave us one of the best TARDIS interiors. It is one of the best Classic Doctor adventures made.
My next one would the 2002 Spider Man film. This is one of my favourite films of all time and one of the best Spider Man films. I was always a big Spider Man fan and finding out he was getting a movie made was a big deal to me. I remember the first time I found out about it was when my dad brought home a video of a Muhammad Ali film just to show me the teaser trailer for it. It was the first superhero film I was really excited about.
My last film would be the animated Transformers film from 1986. One of my all-time favourite childhood films and probably still better than most of the live action films released now. It was the film that really made me a fan of Transformers.