[Keaton421]

You can't beat Ghibli movies, they can fit into most categories.

Maiko-Haan, Ping Pong, Swing Girls, Water Boys, Happiness of the Katakuris, and 69 are hilarious.

Always Sanchoume no Yuuhi (and its sequel) are sweet and pretty amazing movies.

If you're into weird stuff, look up Takashi Miike (director) and Takeshi Kitano (Beat Takeshi, actor and director)

Crows Zero and anything by Akira Kurosawa are good action movies with a brain.

Sadly, there are no good Japanese horror movies. Heck, the only truly scary movies (I don't mean sudden sounds or whatever), in my opinion, are Signs and The Shining.

If I think of more I'll let you know...

Ooh, Ichi the Killer is a good action flick