My take: The Departed
Good ol' Jack Nicholson plays Frank Costello, the kingpin of the Boston mafia in the area of "southie." Early on, he becomes a quasi father figure to Colin Sullivan, a local Irish boy with a father that's notorious for being a small time gangster. Costello takes Sullivan, played almost effortlessly by Matt Damon, under his wing and keeps him there, even when the young lad grows up and joins the Massachusetts State Police. Sullivan through the ranks, making detective quickly and eventually becomes a part of the special investigations unit, specially investigating one Frank Costello.
At seemingly the same time, though we never see them meet, Bill Costigan also becomes a State Trooper and is interviewed by the Special Investigations Unit - as a potential undercover guy. Costigan, played by Leonardo DiCaprio but not looking or sounding like the Leo we know, has an already checkered past, one the cops wouldn't really have to doctor to make a believable gangster out of. Through a series of rapid flash-forwards, we see him getting in to the criminal element - actually serving jail-time for a petty string of crimes, getting involved with the right people, making a name for himself, etc. Eventually he makes his way in to the Costello inner circle, which is when this movie really gets going.
What keeps things on the edge for the viewer is a somewhat Hitchcockian story-telling device - we know who the mole is in the gangster world and cop world, yet neither of them know who the other is. Costigan doesn't even know of the mole inside the police unit until later on, when things seem to be going too smoothly for the criminals; the mental anguish he begins experiencing puts him in a shrink's office - the same shrink that is dating Sullivan it turns out. An intriguing but slightly unbelievable love triangle begins, adding another layer. More layers follow, but I don't want to give spoilers - the ending is full of surprises.
The main thing that bothered me with this movie is the over the top use of gore. There's enough heads exploding in a spray of red here that could rival slasher flicks - by the end of the movie, it had become laugh-out-loud funny to see (though this could have had something to do with who it was happening to...). I won't necessarily complain about the language - it goes hand-in-hand with mob-movies - but I will take a second to gripe about the accents. I'm sure they're very authentic and that everybody in Bahston tahlks that waiee - it's just annoying to listen to (and apparently annoying to keep doing - Nicholson's accent drops a bit towards the end of the movie).
In all though, this is a terrific movie and worthy of the Best Pic nomination it got. Also worthy is the cast - Alec Baldwin, Mark Wahlberg, and Martin Sheen are all terrific in supporting roles. If you're no fan of mob movies though, you won't like it. 9/10