The Matrix and The Thing are definitely in my top 5, but I can't figure out the other three.
I'm struggling with a fourth and fifth at the moment, but I gotta add Dredd:
Dredd's been my absolute favorite comic character and universe since the mid 80's... I remember being so angry at the Stallone one that came out in '95. The new one was fuckin perfect, whether you're a fan of the books or not. Sucks that there won't be a sequel, but it's rewatchable as hell.
I also really, really love the movie "John Dies at the End," but I'm not sure if it's in my top 5. It's close if it's not though.