I'll start with this one: Lucky Number Slevin (2006), 51% rotten meter on rottentomatoes.com.
Why you should watch it:
1) Acting. The cast is great (Ben Kingsley, Stanley Tucci, Morgan Freeman, Bruce Willis, Lucy Liu and Josh Hartnett). Many, including Liu and Hartnett perform their best roles IMO. The tempo of the movie is great and the dialogue has a dark vibrant comedy to it, reminiscent of Pulp fiction. The overall plot is a bit of a stretch, but if you like convoluted crime dramas, this one might just be it for you.
2) Style. The movie has great style. The set design is outstanding. It is a well-shot movie where the appartments the people live in say as much about them as the dialogue.
Piece of dialogue to characterize the movie:
Slevin: This isn't the first time this has happened, you know.
Lindsey: You mean this isn't the first time a crime lord asked you to kill the gay son of a rival gangster to pay off a debt that belongs to a friend whose place you're staying in as a result of losing your job, your apartment, and finding your girlfriend in bed with another guy?
Slevin: No, this is the first time THAT happened, but Nick has been painting me into corners since we were kids.