The first 3 Star Wars movies and the first Indiana Jones
I know that's 4, and while I don't care for these movies any more, no movie will ever provide the experience of seeing those as a young kid ... back in the days where I believed I could do all of those things one day! Seeing ET as a 6 year old was pretty impactful too. Hard to think of many movies I've seen in my adulthood that I would call great, although if I were to look for them, I'd go back in time when they made some decent movies. Everything is crap today.