I've got a few:
Blade Runner - I prefer the Director's Cut that removes the voiceover. But I'll watch the voiceover version just for old time's sake, too.
12 Monkeys - Brad Pitt's best role ever! Love this. And Gilliam. And the story. And... everything.
Ocean's 11 - (The Pitt and Clooney version) I don't know what it is about this movie... I just think it is perfect. I've done film-school analyses of every shot, every line of dialog, and every error in the film. I probably know this movie better than any other movie. It's inexplicable and weird, but I love it.
Waking Ned Devine - Totally enchanting little Irish story, shot on the Isle of Man. And I have an enormous crush on Finnoula Flanagan.
Mad Max - In the so-bad-its-good category. I just love that a bunch of weirdo Aussies poured their heart into this complete disaster of a script, and came up with something... iconic.
The Road Warrior - Mad Max done right, and with a budget. I expect Fury Road to replace this one in my shortlist soon. Fury Road gets all of The Road Warrior right, and then goes even further.
Serenity - Duh. Of course.
Galaxy Quest - The finest, most loving, takedown of geek culture there is. Utter perfection, start to finish.
That's my shortlist of "Dangerous" movies, by which I mean, movies that, if I turn them on, I know I'm not going to do anything else for the next hour and a half.