Natural Born Killers?!? Really?!?
That movie is a steaming pile of shit: as I watched it, I realized immediately that any irony and/or wit was entirely incidental. It was 2 hours of Oliver Stone screaming at the top of his lungs "OMGZ! I MAKE PROFOUND MOVIE ABOUT HOW MEDIA CREATES ULTRAVIOLENTZ!"
No, no, no.
A thousand times no.
The best Valentine's Day film to watch with your GF that is brutal and sick and twisted, but will still make her heart melt?
TRUE ROMANCE.
As a bonus, it has Brad Pitt in his finest role ever.
That is all.
Edit: I may have to check out May, however. So thanks for that recommendation, anyway.