I have remembered a good one for me.
The very first time I saw The Godfather was at the McRobert in Stirling. It had an intermission and a bar, so I managed to grab a drink half way through.
Seeing that movie, for the very first time, on the big screen was tremendous.
I also saw The Rocky Horror Picture Show there, with students performing the film as it was playing behind them. That wasn't quite as good.