Kurosawa is one of my favorite directors. Every film of his that I've seen is very good.
Dreams, for example, may have a couple of sequences that are too corny to my taste, but also some great haunting scenes (the snow storm and the soldier's tunnel stick in memory).
Red Beard made me shiver emotionally all through: a great tale of life and death.
The Seven Samurai is, so far, unsurpassed, as a moral action epic.
Ran is a very strong adaptation of Shakespeare, and has one of the saddest endings, in cinema. Not handkerchief sadness, but the feeling of emptiness and unjustice in all human struggle.
Kagemusha, Sanyuro, The Drunken Angel are also great films.
I haven't seen
Rashomon yet.