Let that be a lesson to y’all. If you want to make it a really memorable evening, be sure to spread a whole bunch of gasoline-soaked rags around before the movie starts, and keep your cigarette lighter handy for the perfect moment.
The Goonies. I saw it when I was about 9 years old in a theater on the Outer Banks of North Carolina. This was the mid- late 80s, and seeing that movie again always reminds me of that happy and carefree time of my life.
Forrest Gump. I saw it when it first came out with my boyfriend – now husband. It was at that time in the beginning of our relationship when we were just starting to realize how totally crazy we were about each other, and that movie just makes me SO happy when I watch it again.
Like Baker said above, mine was Flash Gordon with Max VanSydow.
My mother was in the hospital with cancer and after visiting her my father took me and my little brother to see it.
My mother survived however I think it was the last time my father ever went to the movies.
I have a soft spot for Amelie… 
Married to the Mob, A Fish Called Wanda, and Ernest Saves Christmas. I loved them and look back on them with wonderful memories, because these were the films I saw with my first real girlfriend (i.e.–my first kiss, my first hand-holding, my first … well, they were good movies, too).
A few years later, I saw Hook on a first date with the woman I almost married.
A few years after that, I saw Scent of a Woman with the woman I did marry.
The funny thing is that I’m not much of a movie buff. I’m just as likely to remember movies for these sorts of reasons as I am for the fact that they were well/terribly acted, had great/awful visuals, and so on.
Amelie me too. It is good even without the good experience that went along with it. A big group of my housemates went with me, it was relatively early on in our living together (none of us had known each other before).
That and the fact that my French housemate, who had seen when it came out in France, was so enamoured of Amelie. He showed me a picture in a magazine but I didn’t really get it until I saw the film. Now I’m enamoured of her.