narrowing it down to 3 is simply impossible... if i include Il buono, il brutto, il cattivo, Shawshank redemption, and the Godfather i'll have to exclude Pulp Fiction, 2001, Ronin, raiders of the lost ark, blade runner, ben hur, nightmare before christmas
I love Blade Runner only for how incredibly neo-film noir it is, it is beyond beautiful, it encapsulated everything of the era, reinterpreted it in a thoroughly post modern sci-fi setting projecting how life would be if the 80s sensibilities and socio-economic had carried on for the next few decades becoming more refined and reached their inevitable collapse. That and it achieved the near impossible task of being completely timeless, that film has not dated at all.
Note: I have a TV & film degree. It ruins your ability to just "watch" films, but at the very least, makes you understand why a film is good.
Sorry if this post seems a bit intense, I've missed getting deep over films since coming out of uni