Satan's son ascends to heaven and wages war on evil in the comedy film, Little Nicky. Somehow, this film manages to cost $85 million, which is probably the biggest sin. No, on second though, the most evil thing about this film is the ridiculous Popeye's chicken product placement. Yes, the demon really says, "Popeye's chicken is the shiznit."
If there was any further doubt in your mind that this might not be the best film of all time, here's an excerpt from the wikipedia plot description, "Not knowing what to do, Nicky has Todd kill him so he can go back to Hell and ask his father for advice, but his father has trouble hearing because his ears have fallen off..." Harvey Keitel plays the role of Satan, and manages to get many of the film's sparsely-distributed funny lines, like this interaction:
Satan: I'm sorry. After careful consideration, I regretfully have to decline.
Dan Marino: C'mon, man, I'm just asking, let me win one Super Bowl.
Satan: In exchange for eternal damnation of your soul? You're too nice of a guy for me to want to do that to you, Mr. Marino.
Dan Marino: You did it for Namath.
Satan: Yeah, but Joe was coming here anyways.
Keitel does a great job as Satan, especially considering the character seems intent on reducing wickedness to preserve the balance between good and evil (or, at least, that's what we took from this confusing plot point). This must have been as hard to swallow for the actor as it is for us.