[Kamio]

In term of foreign Film, one of the best I ever saw was "infernal affairs" (2002) it's a police/investigation Film from hong kong and the best film from there I saw.
The rythm and tension is extremely well handled. There is very little violence compared to some of it's brothers, but when it finally erupts it really punches.
It's investigation and it's handled like a collumbo episode in the sence that you know from the start the situation and who did what, there's no mystery, the intrigue is in how the situation will resolve itself, not in finding out who is the bad guy.

I think the best proof of how good the film is, is that hollywood bought the rights and adapted it in the Film "the departed" by Martin Scorsese 4 years later. I haven't watched it but common consensus is that the adaptation is not as good like often.

I know there is also big fighting film culture from hong kong, but it is not a type of film I am into so I can't talk about those.