I love both Gremlins so much... But I'll probably say Men in Black. I always cite this movie as the perfect summer blockbuster, or at least as a solid example of what to aim for in terms of quality.
The story is straight forward but always engaging. The script is great and elevated by an impeccable cast that makes so many of the lines memorable. The whole pacing is particularly on point, everything flows so well and I really can't find any place where the movie would drag.
And there's the production design, cinematography and visual effects, everything was top notch back then and in my opinion still holds up. Icing on the cake, you even have a nice theme composed by Elfman... Yeah, to me it's all perfectly crafted.
I feel like the movie is a bit underrated at times. Sure, it's all subjective, but I definitely put this one alongside other pop culture classics.