I can't choose... If it was asian or chinese movies it'd totally be 2046/In The Mood For Love... Those two films were amazing and heartbreaking...
Hmmm, for the time being I'll say Ichi The Killer. Because uhm... I guess you can sorta say "ero-guro" for it, as Ichi and Kakihara really liked the things they did... Well, it's friggin' freaky and scary. XD