I still haven't seen Eastern Promises. I went into History of Violence without knowing anything as well, and it was pretty crazy.

Little Children is great too.  I read up on the movie before watching it, so all my friends thought it looked like a random chick flick, but they liked it.

Eastern Promises is a solid movie and definitely worth a watch but it didn't shock me like History of Violence did. I think everyone's jaw hits the floor during one scene of that movie.

I also expected Little Children to be a total chick flick. To put it lightly, I was pleasantly surprised. 

You can't go wrong if you start here:

http://www.imdb.com/chart/top

My personal favorite is "Dr. Strangelove or: How I Learned to Stop Worrying and Love the Bomb". It is so damn hilarious.